/*
Copyright 2017 Google LLC

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package spanner

import (
	"encoding/json"
	"fmt"
	"math"
	"math/big"
	"reflect"
	"testing"
	"time"

	"cloud.google.com/go/civil"
	"cloud.google.com/go/internal/testutil"
	"github.com/golang/protobuf/proto"
	proto3 "github.com/golang/protobuf/ptypes/struct"
	"github.com/google/go-cmp/cmp"
	sppb "google.golang.org/genproto/googleapis/spanner/v1"
)

var (
	t1 = mustParseTime("2016-11-15T15:04:05.999999999Z")
	// Boundaries
	t2 = mustParseTime("0001-01-01T00:00:00.000000000Z")
	t3 = mustParseTime("9999-12-31T23:59:59.999999999Z")
	// Local timezone
	t4 = time.Now()
	d1 = mustParseDate("2016-11-15")
	d2 = mustParseDate("1678-01-01")
)

func mustParseTime(s string) time.Time {
	t, err := time.Parse(time.RFC3339Nano, s)
	if err != nil {
		panic(err)
	}
	return t
}

func mustParseDate(s string) civil.Date {
	d, err := civil.ParseDate(s)
	if err != nil {
		panic(err)
	}
	return d
}

type customStructToString struct {
	A string
	B string
}

// Convert the customStructToString
func (c customStructToString) EncodeSpanner() (interface{}, error) {
	return "A-B", nil
}

// Convert to customStructToString
func (c *customStructToString) DecodeSpanner(val interface{}) (err error) {
	c.A = "A"
	c.B = "B"
	return nil
}

type customStructToInt struct {
	A int64
	B int64
}

// Convert the customStructToInt
func (c customStructToInt) EncodeSpanner() (interface{}, error) {
	return 123, nil
}

// Convert to customStructToInt
func (c *customStructToInt) DecodeSpanner(val interface{}) (err error) {
	c.A = 1
	c.B = 23
	return nil
}

type customStructToFloat struct {
	A float64
	B float64
}

// Convert the customStructToFloat
func (c customStructToFloat) EncodeSpanner() (interface{}, error) {
	return 123.123, nil
}

// Convert to customStructToFloat
func (c *customStructToFloat) DecodeSpanner(val interface{}) (err error) {
	c.A = 1.23
	c.B = 12.3
	return nil
}

type customStructToBool struct {
	A bool
	B bool
}

// Convert the customStructToBool
func (c customStructToBool) EncodeSpanner() (interface{}, error) {
	return true, nil
}

// Convert to customStructToBool
func (c *customStructToBool) DecodeSpanner(val interface{}) (err error) {
	c.A = true
	c.B = false
	return nil
}

type customStructToBytes struct {
	A []byte
	B []byte
}

// Convert the customStructToBytes
func (c customStructToBytes) EncodeSpanner() (interface{}, error) {
	return []byte("AB"), nil
}

// Convert to customStructToBytes
func (c *customStructToBytes) DecodeSpanner(val interface{}) (err error) {
	c.A = []byte("A")
	c.B = []byte("B")
	return nil
}

type customStructToTime struct {
	A string
	B string
}

// Convert the customStructToTime
func (c customStructToTime) EncodeSpanner() (interface{}, error) {
	return t1, nil
}

// Convert to customStructToTime
func (c *customStructToTime) DecodeSpanner(val interface{}) (err error) {
	c.A = "A"
	c.B = "B"
	return nil
}

type customStructToDate struct {
	A string
	B string
}

// Convert the customStructToDate
func (c customStructToDate) EncodeSpanner() (interface{}, error) {
	return d1, nil
}

// Convert to customStructToDate
func (c *customStructToDate) DecodeSpanner(val interface{}) (err error) {
	c.A = "A"
	c.B = "B"
	return nil
}

// Test encoding Values.
func TestEncodeValue(t *testing.T) {
	type CustomString string
	type CustomBytes []byte
	type CustomInt64 int64
	type CustomBool bool
	type CustomFloat64 float64
	type CustomTime time.Time
	type CustomDate civil.Date
	type CustomNumeric big.Rat

	type CustomNullString NullString
	type CustomNullInt64 NullInt64
	type CustomNullBool NullBool
	type CustomNullFloat64 NullFloat64
	type CustomNullTime NullTime
	type CustomNullDate NullDate
	type CustomNullNumeric NullNumeric

	sValue := "abc"
	var sNilPtr *string
	iValue := int64(7)
	var iNilPtr *int64
	bValue := true
	var bNilPtr *bool
	fValue := 3.14
	var fNilPtr *float64
	tValue := t1
	var tNilPtr *time.Time
	dValue := d1
	var dNilPtr *civil.Date
	numValuePtr := big.NewRat(12345, 1e3)
	var numNilPtr *big.Rat
	num2ValuePtr := big.NewRat(12345, 1e4)

	var (
		tString  = stringType()
		tInt     = intType()
		tBool    = boolType()
		tFloat   = floatType()
		tBytes   = bytesType()
		tTime    = timeType()
		tDate    = dateType()
		tNumeric = numericType()
	)
	for i, test := range []struct {
		in       interface{}
		want     *proto3.Value
		wantType *sppb.Type
		name     string
	}{
		// STRING / STRING ARRAY:
		{"abc", stringProto("abc"), tString, "string"},
		{NullString{"abc", true}, stringProto("abc"), tString, "NullString with value"},
		{NullString{"abc", false}, nullProto(), tString, "NullString with null"},
		{&sValue, stringProto("abc"), tString, "*string with value"},
		{sNilPtr, nullProto(), tString, "*string with null"},
		{[]string(nil), nullProto(), listType(tString), "null []string"},
		{[]string{"abc", "bcd"}, listProto(stringProto("abc"), stringProto("bcd")), listType(tString), "[]string"},
		{[]NullString{{"abcd", true}, {"xyz", false}}, listProto(stringProto("abcd"), nullProto()), listType(tString), "[]NullString"},
		{[]*string{&sValue, sNilPtr}, listProto(stringProto("abc"), nullProto()), listType(tString), "[]*string"},
		// BYTES / BYTES ARRAY
		{[]byte("foo"), bytesProto([]byte("foo")), tBytes, "[]byte with value"},
		{[]byte(nil), nullProto(), tBytes, "null []byte"},
		{[][]byte{nil, []byte("ab")}, listProto(nullProto(), bytesProto([]byte("ab"))), listType(tBytes), "[][]byte"},
		{[][]byte(nil), nullProto(), listType(tBytes), "null [][]byte"},
		// INT64 / INT64 ARRAY
		{7, intProto(7), tInt, "int"},
		{[]int(nil), nullProto(), listType(tInt), "null []int"},
		{[]int{31, 127}, listProto(intProto(31), intProto(127)), listType(tInt), "[]int"},
		{int64(81), intProto(81), tInt, "int64"},
		{[]int64(nil), nullProto(), listType(tInt), "null []int64"},
		{[]int64{33, 129}, listProto(intProto(33), intProto(129)), listType(tInt), "[]int64"},
		{NullInt64{11, true}, intProto(11), tInt, "NullInt64 with value"},
		{NullInt64{11, false}, nullProto(), tInt, "NullInt64 with null"},
		{&iValue, intProto(7), tInt, "*int64 with value"},
		{iNilPtr, nullProto(), tInt, "*int64 with null"},
		{[]NullInt64{{35, true}, {131, false}}, listProto(intProto(35), nullProto()), listType(tInt), "[]NullInt64"},
		{[]*int64{&iValue, iNilPtr}, listProto(intProto(7), nullProto()), listType(tInt), "[]*int64"},
		// BOOL / BOOL ARRAY
		{true, boolProto(true), tBool, "bool"},
		{NullBool{true, true}, boolProto(true), tBool, "NullBool with value"},
		{NullBool{true, false}, nullProto(), tBool, "NullBool with null"},
		{&bValue, boolProto(true), tBool, "*bool with value"},
		{bNilPtr, nullProto(), tBool, "*bool with null"},
		{[]bool{true, false}, listProto(boolProto(true), boolProto(false)), listType(tBool), "[]bool"},
		{[]NullBool{{true, true}, {true, false}}, listProto(boolProto(true), nullProto()), listType(tBool), "[]NullBool"},
		{[]*bool{&bValue, bNilPtr}, listProto(boolProto(true), nullProto()), listType(tBool), "[]*bool"},
		// FLOAT64 / FLOAT64 ARRAY
		{3.14, floatProto(3.14), tFloat, "float"},
		{NullFloat64{3.1415, true}, floatProto(3.1415), tFloat, "NullFloat64 with value"},
		{NullFloat64{math.Inf(1), true}, floatProto(math.Inf(1)), tFloat, "NullFloat64 with infinity"},
		{NullFloat64{3.14159, false}, nullProto(), tFloat, "NullFloat64 with null"},
		{&fValue, floatProto(3.14), tFloat, "*float64 with value"},
		{fNilPtr, nullProto(), tFloat, "*float64 with null"},
		{[]float64(nil), nullProto(), listType(tFloat), "null []float64"},
		{[]float64{3.141, 0.618, math.Inf(-1)}, listProto(floatProto(3.141), floatProto(0.618), floatProto(math.Inf(-1))), listType(tFloat), "[]float64"},
		{[]NullFloat64{{3.141, true}, {0.618, false}}, listProto(floatProto(3.141), nullProto()), listType(tFloat), "[]NullFloat64"},
		{[]*float64{&fValue, fNilPtr}, listProto(floatProto(3.14), nullProto()), listType(tFloat), "[]NullFloat64"},
		// NUMERIC / NUMERIC ARRAY
		{*numValuePtr, numericProto(numValuePtr), tNumeric, "big.Rat"},
		{numValuePtr, numericProto(numValuePtr), tNumeric, "*big.Rat"},
		{numNilPtr, nullProto(), tNumeric, "*big.Rat with null"},
		{NullNumeric{*numValuePtr, true}, numericProto(numValuePtr), tNumeric, "NullNumeric with value"},
		{NullNumeric{*numValuePtr, false}, nullProto(), tNumeric, "NullNumeric with null"},
		{[]big.Rat(nil), nullProto(), listType(tNumeric), "null []big.Rat"},
		{[]big.Rat{*numValuePtr, *num2ValuePtr}, listProto(numericProto(numValuePtr), numericProto(num2ValuePtr)), listType(tNumeric), "[]big.Rat"},
		{[]NullNumeric{{*numValuePtr, true}, {*numValuePtr, false}}, listProto(numericProto(numValuePtr), nullProto()), listType(tNumeric), "[]NullNumeric"},
		{[]*big.Rat{nil, numValuePtr}, listProto(nullProto(), numericProto(numValuePtr)), listType(tNumeric), "[]*big.Rat"},
		{[]*big.Rat(nil), nullProto(), listType(tNumeric), "null []*big.Rat"},
		// TIMESTAMP / TIMESTAMP ARRAY
		{t1, timeProto(t1), tTime, "time"},
		{NullTime{t1, true}, timeProto(t1), tTime, "NullTime with value"},
		{NullTime{t1, false}, nullProto(), tTime, "NullTime with null"},
		{&tValue, timeProto(t1), tTime, "*time.Time with value"},
		{tNilPtr, nullProto(), tTime, "*time.Time with null"},
		{[]time.Time(nil), nullProto(), listType(tTime), "null []time"},
		{[]time.Time{t1, t2, t3, t4}, listProto(timeProto(t1), timeProto(t2), timeProto(t3), timeProto(t4)), listType(tTime), "[]time"},
		{[]NullTime{{t1, true}, {t1, false}}, listProto(timeProto(t1), nullProto()), listType(tTime), "[]NullTime"},
		{[]*time.Time{&tValue, tNilPtr}, listProto(timeProto(t1), nullProto()), listType(tTime), "[]*time.Time"},
		// DATE / DATE ARRAY
		{d1, dateProto(d1), tDate, "date"},
		{NullDate{d1, true}, dateProto(d1), tDate, "NullDate with value"},
		{NullDate{civil.Date{}, false}, nullProto(), tDate, "NullDate with null"},
		{&dValue, dateProto(d1), tDate, "*civil.Date with value"},
		{dNilPtr, nullProto(), tDate, "*civil.Date with null"},
		{[]civil.Date(nil), nullProto(), listType(tDate), "null []date"},
		{[]civil.Date{d1, d2}, listProto(dateProto(d1), dateProto(d2)), listType(tDate), "[]date"},
		{[]NullDate{{d1, true}, {civil.Date{}, false}}, listProto(dateProto(d1), nullProto()), listType(tDate), "[]NullDate"},
		{[]*civil.Date{&dValue, dNilPtr}, listProto(dateProto(d1), nullProto()), listType(tDate), "[]*civil.Date"},
		// GenericColumnValue
		{GenericColumnValue{tString, stringProto("abc")}, stringProto("abc"), tString, "GenericColumnValue with value"},
		{GenericColumnValue{tString, nullProto()}, nullProto(), tString, "GenericColumnValue with null"},
		// not actually valid (stringProto inside int list), but demonstrates pass-through.
		{
			GenericColumnValue{
				Type:  listType(tInt),
				Value: listProto(intProto(5), nullProto(), stringProto("bcd")),
			},
			listProto(intProto(5), nullProto(), stringProto("bcd")),
			listType(tInt),
			"pass-through",
		},
		// placeholder
		{CommitTimestamp, stringProto(commitTimestampPlaceholderString), tTime, "CommitTimestampPlaceholder"},
		// CUSTOM STRING / CUSTOM STRING ARRAY
		{CustomString("abc"), stringProto("abc"), tString, "CustomString"},
		{CustomNullString{"abc", true}, stringProto("abc"), tString, "CustomNullString with value"},
		{CustomNullString{"abc", false}, nullProto(), tString, "CustomNullString with null"},
		{[]CustomString(nil), nullProto(), listType(tString), "null []CustomString"},
		{[]CustomString{"abc", "bcd"}, listProto(stringProto("abc"), stringProto("bcd")), listType(tString), "[]CustomString"},
		{[]CustomNullString(nil), nullProto(), listType(tString), "null []NullCustomString"},
		{[]CustomNullString{{"abcd", true}, {"xyz", false}}, listProto(stringProto("abcd"), nullProto()), listType(tString), "[]NullCustomString"},
		// CUSTOM BYTES / CUSTOM BYTES ARRAY
		{CustomBytes("foo"), bytesProto([]byte("foo")), tBytes, "CustomBytes with value"},
		{CustomBytes(nil), nullProto(), tBytes, "null CustomBytes"},
		{[]CustomBytes{nil, CustomBytes("ab")}, listProto(nullProto(), bytesProto([]byte("ab"))), listType(tBytes), "[]CustomBytes"},
		{[]CustomBytes(nil), nullProto(), listType(tBytes), "null []CustomBytes"},
		// CUSTOM INT64 / CUSTOM INT64 ARRAY
		{CustomInt64(81), intProto(81), tInt, "CustomInt64"},
		{[]CustomInt64(nil), nullProto(), listType(tInt), "null []CustomInt64"},
		{[]CustomInt64{33, 129}, listProto(intProto(33), intProto(129)), listType(tInt), "[]CustomInt64"},
		{CustomNullInt64{11, true}, intProto(11), tInt, "CustomNullInt64 with value"},
		{CustomNullInt64{11, false}, nullProto(), tInt, "CustomNullInt64 with null"},
		{[]CustomNullInt64(nil), nullProto(), listType(tInt), "null []CustomNullInt64"},
		{[]CustomNullInt64{{35, true}, {131, false}}, listProto(intProto(35), nullProto()), listType(tInt), "[]CustomNullInt64"},
		// CUSTOM BOOL / CUSTOM BOOL ARRAY
		{CustomBool(true), boolProto(true), tBool, "CustomBool"},
		{CustomNullBool{true, true}, boolProto(true), tBool, "CustomNullBool with value"},
		{CustomNullBool{true, false}, nullProto(), tBool, "CustomNullBool with null"},
		{[]CustomBool{true, false}, listProto(boolProto(true), boolProto(false)), listType(tBool), "[]CustomBool"},
		{[]CustomNullBool{{true, true}, {true, false}}, listProto(boolProto(true), nullProto()), listType(tBool), "[]CustomNullBool"},
		// FLOAT64 / FLOAT64 ARRAY
		{CustomFloat64(3.14), floatProto(3.14), tFloat, "CustomFloat64"},
		{CustomNullFloat64{3.1415, true}, floatProto(3.1415), tFloat, "CustomNullFloat64 with value"},
		{CustomNullFloat64{math.Inf(1), true}, floatProto(math.Inf(1)), tFloat, "CustomNullFloat64 with infinity"},
		{CustomNullFloat64{3.14159, false}, nullProto(), tFloat, "CustomNullFloat64 with null"},
		{[]CustomFloat64(nil), nullProto(), listType(tFloat), "null []CustomFloat64"},
		{[]CustomFloat64{3.141, 0.618, CustomFloat64(math.Inf(-1))}, listProto(floatProto(3.141), floatProto(0.618), floatProto(math.Inf(-1))), listType(tFloat), "[]CustomFloat64"},
		{[]CustomNullFloat64(nil), nullProto(), listType(tFloat), "null []CustomNullFloat64"},
		{[]CustomNullFloat64{{3.141, true}, {0.618, false}}, listProto(floatProto(3.141), nullProto()), listType(tFloat), "[]CustomNullFloat64"},
		// CUSTOM TIMESTAMP / CUSTOM TIMESTAMP ARRAY
		{CustomTime(t1), timeProto(t1), tTime, "CustomTime"},
		{CustomNullTime{t1, true}, timeProto(t1), tTime, "CustomNullTime with value"},
		{CustomNullTime{t1, false}, nullProto(), tTime, "CustomNullTime with null"},
		{[]CustomTime(nil), nullProto(), listType(tTime), "null []CustomTime"},
		{[]CustomTime{CustomTime(t1), CustomTime(t2), CustomTime(t3), CustomTime(t4)}, listProto(timeProto(t1), timeProto(t2), timeProto(t3), timeProto(t4)), listType(tTime), "[]CustomTime"},
		{[]CustomNullTime(nil), nullProto(), listType(tTime), "null []CustomNullTime"},
		{[]CustomNullTime{{t1, true}, {t1, false}}, listProto(timeProto(t1), nullProto()), listType(tTime), "[]CustomNullTime"},
		// CUSTOM DATE / CUSTOM DATE ARRAY
		{CustomDate(d1), dateProto(d1), tDate, "CustomDate"},
		{CustomNullDate{d1, true}, dateProto(d1), tDate, "CustomNullDate with value"},
		{CustomNullDate{civil.Date{}, false}, nullProto(), tDate, "CustomNullDate with null"},
		{[]CustomDate(nil), nullProto(), listType(tDate), "null []CustomDate"},
		{[]CustomDate{CustomDate(d1), CustomDate(d2)}, listProto(dateProto(d1), dateProto(d2)), listType(tDate), "[]CustomDate"},
		{[]CustomNullDate(nil), nullProto(), listType(tDate), "null []CustomNullDate"},
		{[]CustomNullDate{{d1, true}, {civil.Date{}, false}}, listProto(dateProto(d1), nullProto()), listType(tDate), "[]NullDate"},
		// CUSTOM STRUCT
		{customStructToString{"A", "B"}, stringProto("A-B"), tString, "a struct to string"},
		{customStructToInt{1, 23}, intProto(123), tInt, "a struct to int"},
		{customStructToFloat{1.23, 12.3}, floatProto(123.123), tFloat, "a struct to float"},
		{customStructToBool{true, false}, boolProto(true), tBool, "a struct to bool"},
		{customStructToBytes{[]byte("A"), []byte("B")}, bytesProto([]byte("AB")), tBytes, "a struct to bytes"},
		{customStructToTime{"A", "B"}, timeProto(tValue), tTime, "a struct to time"},
		{customStructToDate{"A", "B"}, dateProto(dValue), tDate, "a struct to date"},
		// CUSTOM NUMERIC / CUSTOM NUMERIC ARRAY
		{CustomNumeric(*numValuePtr), numericProto(numValuePtr), tNumeric, "CustomNumeric"},
		{CustomNullNumeric{*numValuePtr, true}, numericProto(numValuePtr), tNumeric, "CustomNullNumeric with value"},
		{CustomNullNumeric{*numValuePtr, false}, nullProto(), tNumeric, "CustomNullNumeric with null"},
		{[]CustomNumeric(nil), nullProto(), listType(tNumeric), "null []CustomNumeric"},
		{[]CustomNumeric{CustomNumeric(*numValuePtr), CustomNumeric(*num2ValuePtr)}, listProto(numericProto(numValuePtr), numericProto(num2ValuePtr)), listType(tNumeric), "[]CustomNumeric"},
		{[]CustomNullNumeric(nil), nullProto(), listType(tNumeric), "null []CustomNullNumeric"},
		{[]CustomNullNumeric{{*numValuePtr, true}, {*num2ValuePtr, false}}, listProto(numericProto(numValuePtr), nullProto()), listType(tNumeric), "[]CustomNullNumeric"},
	} {
		got, gotType, err := encodeValue(test.in)
		if err != nil {
			t.Fatalf("#%d (%s): got error during encoding: %v, want nil", i, test.name, err)
		}
		if !testEqual(got, test.want) {
			t.Errorf("#%d (%s): got encode result: %v, want %v", i, test.name, got, test.want)
		}
		if !testEqual(gotType, test.wantType) {
			t.Errorf("#%d (%s): got encode type: %v, want %v", i, test.name, gotType, test.wantType)
		}
	}
}

type encodeTest struct {
	desc     string
	in       interface{}
	want     *proto3.Value
	wantType *sppb.Type
}

func checkStructEncoding(desc string, got *proto3.Value, gotType *sppb.Type,
	want *proto3.Value, wantType *sppb.Type, t *testing.T) {
	if !testEqual(got, want) {
		t.Errorf("Test %s: got encode result: %v, want %v", desc, got, want)
	}
	if !testEqual(gotType, wantType) {
		t.Errorf("Test %s: got encode type: %v, want %v", desc, gotType, wantType)
	}
}

// Testcase code
func encodeStructValue(test encodeTest, t *testing.T) {
	got, gotType, err := encodeValue(test.in)
	if err != nil {
		t.Fatalf("Test %s: got error during encoding: %v, want nil", test.desc, err)
	}
	checkStructEncoding(test.desc, got, gotType, test.want, test.wantType, t)
}

func TestEncodeStructValuePointers(t *testing.T) {
	type structf struct {
		F int `spanner:"ff2"`
	}
	nestedStructProto := structType(mkField("ff2", intType()))

	type testType struct {
		Stringf    string
		Structf    *structf
		ArrStructf []*structf
	}
	testTypeProto := structType(
		mkField("Stringf", stringType()),
		mkField("Structf", nestedStructProto),
		mkField("ArrStructf", listType(nestedStructProto)))

	for _, test := range []encodeTest{
		{
			"Pointer to Go struct with pointers-to-(array)-struct fields.",
			&testType{"hello", &structf{50}, []*structf{{30}, {40}}},
			listProto(
				stringProto("hello"),
				listProto(intProto(50)),
				listProto(
					listProto(intProto(30)),
					listProto(intProto(40)))),
			testTypeProto,
		},
		{
			"Nil pointer to Go struct representing a NULL struct value.",
			(*testType)(nil),
			nullProto(),
			testTypeProto,
		},
		{
			"Slice of pointers to Go structs with NULL and non-NULL elements.",
			[]*testType{
				(*testType)(nil),
				{"hello", nil, []*structf{nil, {40}}},
				{"world", &structf{70}, nil},
			},
			listProto(
				nullProto(),
				listProto(
					stringProto("hello"),
					nullProto(),
					listProto(nullProto(), listProto(intProto(40)))),
				listProto(
					stringProto("world"),
					listProto(intProto(70)),
					nullProto())),
			listType(testTypeProto),
		},
		{
			"Nil slice of pointers to structs representing a NULL array of structs.",
			[]*testType(nil),
			nullProto(),
			listType(testTypeProto),
		},
		{
			"Empty slice of pointers to structs representing an empty array of structs.",
			[]*testType{},
			listProto(),
			listType(testTypeProto),
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestEncodeStructValueErrors(t *testing.T) {
	type Embedded struct {
		A int
	}
	type embedded struct {
		B bool
	}
	x := 0

	for _, test := range []struct {
		desc    string
		in      interface{}
		wantErr error
	}{
		{
			"Unsupported embedded fields.",
			struct{ Embedded }{Embedded{10}},
			errUnsupportedEmbeddedStructFields("Embedded"),
		},
		{
			"Unsupported pointer to embedded fields.",
			struct{ *Embedded }{&Embedded{10}},
			errUnsupportedEmbeddedStructFields("Embedded"),
		},
		{
			"Unsupported embedded + unexported fields.",
			struct {
				int
				*bool
				embedded
			}{10, nil, embedded{false}},
			errUnsupportedEmbeddedStructFields("int"),
		},
		{
			"Unsupported type.",
			(**struct{})(nil),
			errEncoderUnsupportedType((**struct{})(nil)),
		},
		{
			"Unsupported type.",
			3,
			errEncoderUnsupportedType(3),
		},
		{
			"Unsupported type.",
			&x,
			errEncoderUnsupportedType(&x),
		},
	} {
		_, _, got := encodeStruct(test.in)
		if got == nil || !testEqual(test.wantErr, got) {
			t.Errorf("Test: %s, expected error %v during decoding, got %v", test.desc, test.wantErr, got)
		}
	}
}

func TestEncodeStructValueArrayStructFields(t *testing.T) {
	type structf struct {
		Intff int
	}

	structfType := structType(mkField("Intff", intType()))
	for _, test := range []encodeTest{
		{
			"Unnamed array-of-struct-typed field.",
			struct {
				Intf       int
				ArrStructf []structf `spanner:""`
			}{10, []structf{{1}, {2}}},
			listProto(
				intProto(10),
				listProto(
					listProto(intProto(1)),
					listProto(intProto(2)))),
			structType(
				mkField("Intf", intType()),
				mkField("", listType(structfType))),
		},
		{
			"Null array-of-struct-typed field.",
			struct {
				Intf       int
				ArrStructf []structf
			}{10, []structf(nil)},
			listProto(intProto(10), nullProto()),
			structType(
				mkField("Intf", intType()),
				mkField("ArrStructf", listType(structfType))),
		},
		{
			"Array-of-struct-typed field representing empty array.",
			struct {
				Intf       int
				ArrStructf []structf
			}{10, []structf{}},
			listProto(intProto(10), listProto([]*proto3.Value{}...)),
			structType(
				mkField("Intf", intType()),
				mkField("ArrStructf", listType(structfType))),
		},
		{
			"Array-of-struct-typed field with nullable struct elements.",
			struct {
				Intf       int
				ArrStructf []*structf
			}{
				10,
				[]*structf{(*structf)(nil), {1}},
			},
			listProto(
				intProto(10),
				listProto(
					nullProto(),
					listProto(intProto(1)))),
			structType(
				mkField("Intf", intType()),
				mkField("ArrStructf", listType(structfType))),
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestEncodeStructValueStructFields(t *testing.T) {
	type structf struct {
		Intff int
	}
	structfType := structType(mkField("Intff", intType()))
	for _, test := range []encodeTest{
		{
			"Named struct-type field.",
			struct {
				Intf    int
				Structf structf
			}{10, structf{10}},
			listProto(intProto(10), listProto(intProto(10))),
			structType(
				mkField("Intf", intType()),
				mkField("Structf", structfType)),
		},
		{
			"Unnamed struct-type field.",
			struct {
				Intf    int
				Structf structf `spanner:""`
			}{10, structf{10}},
			listProto(intProto(10), listProto(intProto(10))),
			structType(
				mkField("Intf", intType()),
				mkField("", structfType)),
		},
		{
			"Duplicate struct-typed field.",
			struct {
				Structf1 structf `spanner:""`
				Structf2 structf `spanner:""`
			}{structf{10}, structf{20}},
			listProto(listProto(intProto(10)), listProto(intProto(20))),
			structType(
				mkField("", structfType),
				mkField("", structfType)),
		},
		{
			"Null struct-typed field.",
			struct {
				Intf    int
				Structf *structf
			}{10, nil},
			listProto(intProto(10), nullProto()),
			structType(
				mkField("Intf", intType()),
				mkField("Structf", structfType)),
		},
		{
			"Empty struct-typed field.",
			struct {
				Intf    int
				Structf struct{}
			}{10, struct{}{}},
			listProto(intProto(10), listProto([]*proto3.Value{}...)),
			structType(
				mkField("Intf", intType()),
				mkField("Structf", structType([]*sppb.StructType_Field{}...))),
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestEncodeStructValueFieldNames(t *testing.T) {
	type embedded struct {
		B bool
	}

	for _, test := range []encodeTest{
		{
			"Duplicate fields.",
			struct {
				Field1    int `spanner:"field"`
				DupField1 int `spanner:"field"`
			}{10, 20},
			listProto(intProto(10), intProto(20)),
			structType(
				mkField("field", intType()),
				mkField("field", intType())),
		},
		{
			"Duplicate Fields (different types).",
			struct {
				IntField    int    `spanner:"field"`
				StringField string `spanner:"field"`
			}{10, "abc"},
			listProto(intProto(10), stringProto("abc")),
			structType(
				mkField("field", intType()),
				mkField("field", stringType())),
		},
		{
			"Duplicate unnamed fields.",
			struct {
				Dup  int `spanner:""`
				Dup1 int `spanner:""`
			}{10, 20},
			listProto(intProto(10), intProto(20)),
			structType(
				mkField("", intType()),
				mkField("", intType())),
		},
		{
			"Named and unnamed fields.",
			struct {
				Field  string
				Field1 int    `spanner:""`
				Field2 string `spanner:"field"`
			}{"abc", 10, "def"},
			listProto(stringProto("abc"), intProto(10), stringProto("def")),
			structType(
				mkField("Field", stringType()),
				mkField("", intType()),
				mkField("field", stringType())),
		},
		{
			"Ignored unexported fields.",
			struct {
				Field  int
				field  bool
				Field1 string `spanner:"field"`
			}{10, false, "abc"},
			listProto(intProto(10), stringProto("abc")),
			structType(
				mkField("Field", intType()),
				mkField("field", stringType())),
		},
		{
			"Ignored unexported struct/slice fields.",
			struct {
				a      []*embedded
				b      []embedded
				c      embedded
				d      *embedded
				Field1 string `spanner:"field"`
			}{nil, nil, embedded{}, nil, "def"},
			listProto(stringProto("def")),
			structType(
				mkField("field", stringType())),
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestEncodeStructValueBasicFields(t *testing.T) {
	type CustomString string
	type CustomBytes []byte
	type CustomInt64 int64
	type CustomBool bool
	type CustomFloat64 float64
	type CustomTime time.Time
	type CustomDate civil.Date

	type CustomNullString NullString
	type CustomNullInt64 NullInt64
	type CustomNullBool NullBool
	type CustomNullFloat64 NullFloat64
	type CustomNullTime NullTime
	type CustomNullDate NullDate

	sValue := "abc"
	iValue := int64(300)
	bValue := false
	fValue := 3.45
	tValue := t1
	dValue := d1

	StructTypeProto := structType(
		mkField("Stringf", stringType()),
		mkField("Intf", intType()),
		mkField("Boolf", boolType()),
		mkField("Floatf", floatType()),
		mkField("Bytef", bytesType()),
		mkField("Timef", timeType()),
		mkField("Datef", dateType()))

	for _, test := range []encodeTest{
		{
			"Basic types.",
			struct {
				Stringf string
				Intf    int
				Boolf   bool
				Floatf  float64
				Bytef   []byte
				Timef   time.Time
				Datef   civil.Date
			}{"abc", 300, false, 3.45, []byte("foo"), t1, d1},
			listProto(
				stringProto("abc"),
				intProto(300),
				boolProto(false),
				floatProto(3.45),
				bytesProto([]byte("foo")),
				timeProto(t1),
				dateProto(d1)),
			StructTypeProto,
		},
		{
			"Pointers to basic types.",
			struct {
				Stringf *string
				Intf    *int64
				Boolf   *bool
				Floatf  *float64
				Bytef   []byte
				Timef   *time.Time
				Datef   *civil.Date
			}{&sValue, &iValue, &bValue, &fValue, []byte("foo"), &tValue, &dValue},
			listProto(
				stringProto("abc"),
				intProto(300),
				boolProto(false),
				floatProto(3.45),
				bytesProto([]byte("foo")),
				timeProto(t1),
				dateProto(d1)),
			StructTypeProto,
		},
		{
			"Pointers to basic types with null values.",
			struct {
				Stringf *string
				Intf    *int64
				Boolf   *bool
				Floatf  *float64
				Bytef   []byte
				Timef   *time.Time
				Datef   *civil.Date
			}{nil, nil, nil, nil, nil, nil, nil},
			listProto(
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto()),
			StructTypeProto,
		},
		{
			"Basic custom types.",
			struct {
				Stringf CustomString
				Intf    CustomInt64
				Boolf   CustomBool
				Floatf  CustomFloat64
				Bytef   CustomBytes
				Timef   CustomTime
				Datef   CustomDate
			}{"abc", 300, false, 3.45, []byte("foo"), CustomTime(t1), CustomDate(d1)},
			listProto(
				stringProto("abc"),
				intProto(300),
				boolProto(false),
				floatProto(3.45),
				bytesProto([]byte("foo")),
				timeProto(t1),
				dateProto(d1)),
			StructTypeProto,
		},
		{
			"Basic types null values.",
			struct {
				Stringf NullString
				Intf    NullInt64
				Boolf   NullBool
				Floatf  NullFloat64
				Bytef   []byte
				Timef   NullTime
				Datef   NullDate
			}{
				NullString{"abc", false},
				NullInt64{4, false},
				NullBool{false, false},
				NullFloat64{5.6, false},
				nil,
				NullTime{t1, false},
				NullDate{d1, false},
			},
			listProto(
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto()),
			StructTypeProto,
		},
		{
			"Basic custom types null values.",
			struct {
				Stringf CustomNullString
				Intf    CustomNullInt64
				Boolf   CustomNullBool
				Floatf  CustomNullFloat64
				Bytef   CustomBytes
				Timef   CustomNullTime
				Datef   CustomNullDate
			}{
				CustomNullString{"abc", false},
				CustomNullInt64{4, false},
				CustomNullBool{false, false},
				CustomNullFloat64{5.6, false},
				nil,
				CustomNullTime{t1, false},
				CustomNullDate{d1, false},
			},
			listProto(
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto()),
			StructTypeProto,
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestEncodeStructValueArrayFields(t *testing.T) {
	type CustomString string
	type CustomBytes []byte
	type CustomInt64 int64
	type CustomBool bool
	type CustomFloat64 float64
	type CustomTime time.Time
	type CustomDate civil.Date

	type CustomNullString NullString
	type CustomNullInt64 NullInt64
	type CustomNullBool NullBool
	type CustomNullFloat64 NullFloat64
	type CustomNullTime NullTime
	type CustomNullDate NullDate

	sValue := "def"
	var sNilPtr *string
	iValue := int64(68)
	var iNilPtr *int64
	bValue := true
	var bNilPtr *bool
	fValue := 3.14
	var fNilPtr *float64
	tValue := t1
	var tNilPtr *time.Time
	dValue := d1
	var dNilPtr *civil.Date

	StructTypeProto := structType(
		mkField("Stringf", listType(stringType())),
		mkField("Intf", listType(intType())),
		mkField("Int64f", listType(intType())),
		mkField("Boolf", listType(boolType())),
		mkField("Floatf", listType(floatType())),
		mkField("Bytef", listType(bytesType())),
		mkField("Timef", listType(timeType())),
		mkField("Datef", listType(dateType())))

	for _, test := range []encodeTest{
		{
			"Arrays of basic types with non-nullable elements",
			struct {
				Stringf []string
				Intf    []int
				Int64f  []int64
				Boolf   []bool
				Floatf  []float64
				Bytef   [][]byte
				Timef   []time.Time
				Datef   []civil.Date
			}{
				[]string{"abc", "def"},
				[]int{4, 67},
				[]int64{5, 68},
				[]bool{false, true},
				[]float64{3.45, 0.93},
				[][]byte{[]byte("foo"), nil},
				[]time.Time{t1, t2},
				[]civil.Date{d1, d2},
			},
			listProto(
				listProto(stringProto("abc"), stringProto("def")),
				listProto(intProto(4), intProto(67)),
				listProto(intProto(5), intProto(68)),
				listProto(boolProto(false), boolProto(true)),
				listProto(floatProto(3.45), floatProto(0.93)),
				listProto(bytesProto([]byte("foo")), nullProto()),
				listProto(timeProto(t1), timeProto(t2)),
				listProto(dateProto(d1), dateProto(d2))),
			StructTypeProto,
		},
		{
			"Arrays of basic custom types with non-nullable elements",
			struct {
				Stringf []CustomString
				Intf    []CustomInt64
				Int64f  []CustomInt64
				Boolf   []CustomBool
				Floatf  []CustomFloat64
				Bytef   []CustomBytes
				Timef   []CustomTime
				Datef   []CustomDate
			}{
				[]CustomString{"abc", "def"},
				[]CustomInt64{4, 67},
				[]CustomInt64{5, 68},
				[]CustomBool{false, true},
				[]CustomFloat64{3.45, 0.93},
				[]CustomBytes{[]byte("foo"), nil},
				[]CustomTime{CustomTime(t1), CustomTime(t2)},
				[]CustomDate{CustomDate(d1), CustomDate(d2)},
			},
			listProto(
				listProto(stringProto("abc"), stringProto("def")),
				listProto(intProto(4), intProto(67)),
				listProto(intProto(5), intProto(68)),
				listProto(boolProto(false), boolProto(true)),
				listProto(floatProto(3.45), floatProto(0.93)),
				listProto(bytesProto([]byte("foo")), nullProto()),
				listProto(timeProto(t1), timeProto(t2)),
				listProto(dateProto(d1), dateProto(d2))),
			StructTypeProto,
		},
		{
			"Arrays of basic types with nullable elements.",
			struct {
				Stringf []NullString
				Intf    []NullInt64
				Int64f  []NullInt64
				Boolf   []NullBool
				Floatf  []NullFloat64
				Bytef   [][]byte
				Timef   []NullTime
				Datef   []NullDate
			}{
				[]NullString{{"abc", false}, {"def", true}},
				[]NullInt64{{4, false}, {67, true}},
				[]NullInt64{{5, false}, {68, true}},
				[]NullBool{{true, false}, {false, true}},
				[]NullFloat64{{3.45, false}, {0.93, true}},
				[][]byte{[]byte("foo"), nil},
				[]NullTime{{t1, false}, {t2, true}},
				[]NullDate{{d1, false}, {d2, true}},
			},
			listProto(
				listProto(nullProto(), stringProto("def")),
				listProto(nullProto(), intProto(67)),
				listProto(nullProto(), intProto(68)),
				listProto(nullProto(), boolProto(false)),
				listProto(nullProto(), floatProto(0.93)),
				listProto(bytesProto([]byte("foo")), nullProto()),
				listProto(nullProto(), timeProto(t2)),
				listProto(nullProto(), dateProto(d2))),
			StructTypeProto,
		},
		{
			"Arrays of pointers to basic types with nullable elements.",
			struct {
				Stringf []*string
				Intf    []*int64
				Int64f  []*int64
				Boolf   []*bool
				Floatf  []*float64
				Bytef   [][]byte
				Timef   []*time.Time
				Datef   []*civil.Date
			}{
				[]*string{sNilPtr, &sValue},
				[]*int64{iNilPtr, &iValue},
				[]*int64{iNilPtr, &iValue},
				[]*bool{bNilPtr, &bValue},
				[]*float64{fNilPtr, &fValue},
				[][]byte{[]byte("foo"), nil},
				[]*time.Time{tNilPtr, &tValue},
				[]*civil.Date{dNilPtr, &dValue},
			},
			listProto(
				listProto(nullProto(), stringProto("def")),
				listProto(nullProto(), intProto(68)),
				listProto(nullProto(), intProto(68)),
				listProto(nullProto(), boolProto(true)),
				listProto(nullProto(), floatProto(3.14)),
				listProto(bytesProto([]byte("foo")), nullProto()),
				listProto(nullProto(), timeProto(t1)),
				listProto(nullProto(), dateProto(d1))),
			StructTypeProto,
		},
		{
			"Arrays of basic custom types with nullable elements.",
			struct {
				Stringf []CustomNullString
				Intf    []CustomNullInt64
				Int64f  []CustomNullInt64
				Boolf   []CustomNullBool
				Floatf  []CustomNullFloat64
				Bytef   []CustomBytes
				Timef   []CustomNullTime
				Datef   []CustomNullDate
			}{
				[]CustomNullString{{"abc", false}, {"def", true}},
				[]CustomNullInt64{{4, false}, {67, true}},
				[]CustomNullInt64{{5, false}, {68, true}},
				[]CustomNullBool{{true, false}, {false, true}},
				[]CustomNullFloat64{{3.45, false}, {0.93, true}},
				[]CustomBytes{[]byte("foo"), nil},
				[]CustomNullTime{{t1, false}, {t2, true}},
				[]CustomNullDate{{d1, false}, {d2, true}},
			},
			listProto(
				listProto(nullProto(), stringProto("def")),
				listProto(nullProto(), intProto(67)),
				listProto(nullProto(), intProto(68)),
				listProto(nullProto(), boolProto(false)),
				listProto(nullProto(), floatProto(0.93)),
				listProto(bytesProto([]byte("foo")), nullProto()),
				listProto(nullProto(), timeProto(t2)),
				listProto(nullProto(), dateProto(d2))),
			StructTypeProto,
		},
		{
			"Null arrays of basic types.",
			struct {
				Stringf []NullString
				Intf    []NullInt64
				Int64f  []NullInt64
				Boolf   []NullBool
				Floatf  []NullFloat64
				Bytef   [][]byte
				Timef   []NullTime
				Datef   []NullDate
			}{
				nil,
				nil,
				nil,
				nil,
				nil,
				nil,
				nil,
				nil,
			},
			listProto(
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto()),
			StructTypeProto,
		},
		{
			"Null arrays of basic custom types.",
			struct {
				Stringf []CustomNullString
				Intf    []CustomNullInt64
				Int64f  []CustomNullInt64
				Boolf   []CustomNullBool
				Floatf  []CustomNullFloat64
				Bytef   []CustomBytes
				Timef   []CustomNullTime
				Datef   []CustomNullDate
			}{
				nil,
				nil,
				nil,
				nil,
				nil,
				nil,
				nil,
				nil,
			},
			listProto(
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto(),
				nullProto()),
			StructTypeProto,
		},
	} {
		encodeStructValue(test, t)
	}
}

// Test decoding Values.
func TestDecodeValue(t *testing.T) {
	type CustomString string
	type CustomBytes []byte
	type CustomInt64 int64
	type CustomBool bool
	type CustomFloat64 float64
	type CustomTime time.Time
	type CustomDate civil.Date
	type CustomNumeric big.Rat

	type CustomNullString NullString
	type CustomNullInt64 NullInt64
	type CustomNullBool NullBool
	type CustomNullFloat64 NullFloat64
	type CustomNullTime NullTime
	type CustomNullDate NullDate
	type CustomNullNumeric NullNumeric

	// Pointer values.
	sValue := "abc"
	var sNilPtr *string
	s2Value := "bcd"

	iValue := int64(15)
	var iNilPtr *int64
	i1Value := int64(91)
	i2Value := int64(87)

	bValue := true
	var bNilPtr *bool
	b2Value := false

	fValue := 3.14
	var fNilPtr *float64
	f2Value := 6.626

	numValuePtr := big.NewRat(12345, 1e3)
	var numNilPtr *big.Rat
	num2ValuePtr := big.NewRat(12345, 1e4)

	tValue := t1
	var tNilPtr *time.Time
	t2Value := t2

	dValue := d1
	var dNilPtr *civil.Date
	d2Value := d2

	for _, test := range []struct {
		desc      string
		proto     *proto3.Value
		protoType *sppb.Type
		want      interface{}
		wantErr   bool
	}{
		// STRING
		{desc: "decode STRING to string", proto: stringProto("abc"), protoType: stringType(), want: "abc"},
		{desc: "decode NULL to string", proto: nullProto(), protoType: stringType(), want: "abc", wantErr: true},
		{desc: "decode STRING to *string", proto: stringProto("abc"), protoType: stringType(), want: &sValue},
		{desc: "decode NULL to *string", proto: nullProto(), protoType: stringType(), want: sNilPtr},
		{desc: "decode STRING to NullString", proto: stringProto("abc"), protoType: stringType(), want: NullString{"abc", true}},
		{desc: "decode NULL to NullString", proto: nullProto(), protoType: stringType(), want: NullString{}},
		// STRING ARRAY with []NullString
		{desc: "decode ARRAY<STRING> to []NullString", proto: listProto(stringProto("abc"), nullProto(), stringProto("bcd")), protoType: listType(stringType()), want: []NullString{{"abc", true}, {}, {"bcd", true}}},
		{desc: "decode NULL to []NullString", proto: nullProto(), protoType: listType(stringType()), want: []NullString(nil)},
		// STRING ARRAY with []string
		{desc: "decode ARRAY<STRING> to []string", proto: listProto(stringProto("abc"), stringProto("bcd")), protoType: listType(stringType()), want: []string{"abc", "bcd"}},
		// STRING ARRAY with []*string
		{desc: "decode ARRAY<STRING> to []*string", proto: listProto(stringProto("abc"), nullProto(), stringProto("bcd")), protoType: listType(stringType()), want: []*string{&sValue, sNilPtr, &s2Value}},
		{desc: "decode NULL to []*string", proto: nullProto(), protoType: listType(stringType()), want: []*string(nil)},
		// BYTES
		{desc: "decode BYTES to []byte", proto: bytesProto([]byte("ab")), protoType: bytesType(), want: []byte("ab")},
		{desc: "decode NULL to []byte", proto: nullProto(), protoType: bytesType(), want: []byte(nil)},
		// BYTES ARRAY
		{desc: "decode ARRAY<BYTES> to [][]byte", proto: listProto(bytesProto([]byte("ab")), nullProto()), protoType: listType(bytesType()), want: [][]byte{[]byte("ab"), nil}},
		{desc: "decode NULL to [][]byte", proto: nullProto(), protoType: listType(bytesType()), want: [][]byte(nil)},
		//INT64
		{desc: "decode INT64 to int64", proto: intProto(15), protoType: intType(), want: int64(15)},
		{desc: "decode NULL to int64", proto: nullProto(), protoType: intType(), want: int64(0), wantErr: true},
		{desc: "decode INT64 to *int64", proto: intProto(15), protoType: intType(), want: &iValue},
		{desc: "decode NULL to *int64", proto: nullProto(), protoType: intType(), want: iNilPtr},
		{desc: "decode INT64 to NullInt64", proto: intProto(15), protoType: intType(), want: NullInt64{15, true}},
		{desc: "decode NULL to NullInt64", proto: nullProto(), protoType: intType(), want: NullInt64{}},
		// INT64 ARRAY with []NullInt64
		{desc: "decode ARRAY<INT64> to []NullInt64", proto: listProto(intProto(91), nullProto(), intProto(87)), protoType: listType(intType()), want: []NullInt64{{91, true}, {}, {87, true}}},
		{desc: "decode NULL to []NullInt64", proto: nullProto(), protoType: listType(intType()), want: []NullInt64(nil)},
		// INT64 ARRAY with []int64
		{desc: "decode ARRAY<INT64> to []int64", proto: listProto(intProto(91), intProto(87)), protoType: listType(intType()), want: []int64{91, 87}},
		// INT64 ARRAY with []*int64
		{desc: "decode ARRAY<INT64> to []*int64", proto: listProto(intProto(91), nullProto(), intProto(87)), protoType: listType(intType()), want: []*int64{&i1Value, nil, &i2Value}},
		{desc: "decode NULL to []*int64", proto: nullProto(), protoType: listType(intType()), want: []*int64(nil)},
		// BOOL
		{desc: "decode BOOL to bool", proto: boolProto(true), protoType: boolType(), want: true},
		{desc: "decode NULL to bool", proto: nullProto(), protoType: boolType(), want: true, wantErr: true},
		{desc: "decode BOOL to *bool", proto: boolProto(true), protoType: boolType(), want: &bValue},
		{desc: "decode NULL to *bool", proto: nullProto(), protoType: boolType(), want: bNilPtr},
		{desc: "decode BOOL to NullBool", proto: boolProto(true), protoType: boolType(), want: NullBool{true, true}},
		{desc: "decode BOOL to NullBool", proto: nullProto(), protoType: boolType(), want: NullBool{}},
		// BOOL ARRAY with []NullBool
		{desc: "decode ARRAY<BOOL> to []NullBool", proto: listProto(boolProto(true), boolProto(false), nullProto()), protoType: listType(boolType()), want: []NullBool{{true, true}, {false, true}, {}}},
		{desc: "decode NULL to []NullBool", proto: nullProto(), protoType: listType(boolType()), want: []NullBool(nil)},
		// BOOL ARRAY with []bool
		{desc: "decode ARRAY<BOOL> to []bool", proto: listProto(boolProto(true), boolProto(false)), protoType: listType(boolType()), want: []bool{true, false}},
		// BOOL ARRAY with []*bool
		{desc: "decode ARRAY<BOOL> to []*bool", proto: listProto(boolProto(true), nullProto(), boolProto(false)), protoType: listType(boolType()), want: []*bool{&bValue, bNilPtr, &b2Value}},
		{desc: "decode NULL to []*bool", proto: nullProto(), protoType: listType(boolType()), want: []*bool(nil)},
		// FLOAT64
		{desc: "decode FLOAT64 to float64", proto: floatProto(3.14), protoType: floatType(), want: 3.14},
		{desc: "decode NULL to float64", proto: nullProto(), protoType: floatType(), want: 0.00, wantErr: true},
		{desc: "decode FLOAT64 to *float64", proto: floatProto(3.14), protoType: floatType(), want: &fValue},
		{desc: "decode NULL to *float64", proto: nullProto(), protoType: floatType(), want: fNilPtr},
		{desc: "decode FLOAT64 to NullFloat64", proto: floatProto(3.14), protoType: floatType(), want: NullFloat64{3.14, true}},
		{desc: "decode NULL to NullFloat64", proto: nullProto(), protoType: floatType(), want: NullFloat64{}},
		// FLOAT64 ARRAY with []NullFloat64
		{desc: "decode ARRAY<FLOAT64> to []NullFloat64", proto: listProto(floatProto(math.Inf(1)), floatProto(math.Inf(-1)), nullProto(), floatProto(3.1)), protoType: listType(floatType()), want: []NullFloat64{{math.Inf(1), true}, {math.Inf(-1), true}, {}, {3.1, true}}},
		{desc: "decode NULL to []NullFloat64", proto: nullProto(), protoType: listType(floatType()), want: []NullFloat64(nil)},
		// FLOAT64 ARRAY with []float64
		{desc: "decode ARRAY<FLOAT64> to []float64", proto: listProto(floatProto(math.Inf(1)), floatProto(math.Inf(-1)), floatProto(3.1)), protoType: listType(floatType()), want: []float64{math.Inf(1), math.Inf(-1), 3.1}},
		// FLOAT64 ARRAY with []*float64
		{desc: "decode ARRAY<FLOAT64> to []*float64", proto: listProto(floatProto(fValue), nullProto(), floatProto(f2Value)), protoType: listType(floatType()), want: []*float64{&fValue, nil, &f2Value}},
		{desc: "decode NULL to []*float64", proto: nullProto(), protoType: listType(floatType()), want: []*float64(nil)},
		// NUMERIC
		{desc: "decode NUMERIC to big.Rat", proto: numericProto(numValuePtr), protoType: numericType(), want: *numValuePtr},
		{desc: "decode NUMERIC to NullNumeric", proto: numericProto(numValuePtr), protoType: numericType(), want: NullNumeric{*numValuePtr, true}},
		{desc: "decode NULL to NullNumeric", proto: nullProto(), protoType: numericType(), want: NullNumeric{}},
		{desc: "decode NUMERIC to *big.Rat", proto: numericProto(numValuePtr), protoType: numericType(), want: numValuePtr},
		{desc: "decode NULL to *big.Rat", proto: nullProto(), protoType: numericType(), want: numNilPtr},
		// NUMERIC ARRAY with []NullNumeric
		{desc: "decode ARRAY<Numeric> to []NullNumeric", proto: listProto(numericProto(numValuePtr), numericProto(num2ValuePtr), nullProto()), protoType: listType(numericType()), want: []NullNumeric{{*numValuePtr, true}, {*num2ValuePtr, true}, {}}},
		{desc: "decode NULL to []NullNumeric", proto: nullProto(), protoType: listType(numericType()), want: []NullNumeric(nil)},
		// NUMERIC ARRAY with []big.Rat
		{desc: "decode ARRAY<NUMERIC> to []big.Rat", proto: listProto(numericProto(numValuePtr), numericProto(num2ValuePtr)), protoType: listType(numericType()), want: []big.Rat{*numValuePtr, *num2ValuePtr}},
		// NUMERIC ARRAY with []*big.Rat
		{desc: "decode ARRAY<NUMERIC> to []*big.Rat", proto: listProto(numericProto(numValuePtr), nullProto(), numericProto(num2ValuePtr)), protoType: listType(numericType()), want: []*big.Rat{numValuePtr, nil, num2ValuePtr}},
		{desc: "decode NULL to []*big.Rat", proto: nullProto(), protoType: listType(numericType()), want: []*big.Rat(nil)},
		// TIMESTAMP
		{desc: "decode TIMESTAMP to time.Time", proto: timeProto(t1), protoType: timeType(), want: t1},
		{desc: "decode TIMESTAMP to NullTime", proto: timeProto(t1), protoType: timeType(), want: NullTime{t1, true}},
		{desc: "decode NULL to NullTime", proto: nullProto(), protoType: timeType(), want: NullTime{}},
		{desc: "decode TIMESTAMP to *time.Time", proto: timeProto(t1), protoType: timeType(), want: &tValue},
		{desc: "decode NULL to *time.Time", proto: nullProto(), protoType: timeType(), want: tNilPtr},
		{desc: "decode INT64 to time.Time", proto: intProto(7), protoType: timeType(), want: time.Time{}, wantErr: true},
		// TIMESTAMP ARRAY with []NullTime
		{desc: "decode ARRAY<TIMESTAMP> to []NullTime", proto: listProto(timeProto(t1), timeProto(t2), timeProto(t3), nullProto()), protoType: listType(timeType()), want: []NullTime{{t1, true}, {t2, true}, {t3, true}, {}}},
		{desc: "decode NULL to []NullTime", proto: nullProto(), protoType: listType(timeType()), want: []NullTime(nil)},
		// TIMESTAMP ARRAY with []time.Time
		{desc: "decode ARRAY<TIMESTAMP> to []time.Time", proto: listProto(timeProto(t1), timeProto(t2), timeProto(t3)), protoType: listType(timeType()), want: []time.Time{t1, t2, t3}},
		// TIMESTAMP ARRAY with []*time.Time
		{desc: "decode ARRAY<TIMESTAMP> to []*time.Time", proto: listProto(timeProto(t1), nullProto(), timeProto(t2)), protoType: listType(timeType()), want: []*time.Time{&tValue, nil, &t2Value}},
		{desc: "decode NULL to []*time.Time", proto: nullProto(), protoType: listType(timeType()), want: []*time.Time(nil)},
		// DATE
		{desc: "decode DATE to civil.Date", proto: dateProto(d1), protoType: dateType(), want: d1},
		{desc: "decode DATE to NullDate", proto: dateProto(d1), protoType: dateType(), want: NullDate{d1, true}},
		{desc: "decode NULL to NullDate", proto: nullProto(), protoType: dateType(), want: NullDate{}},
		{desc: "decode DATE to *civil.Date", proto: dateProto(d1), protoType: dateType(), want: &dValue},
		{desc: "decode NULL to *civil.Date", proto: nullProto(), protoType: dateType(), want: dNilPtr},
		// DATE ARRAY with []NullDate
		{desc: "decode ARRAY<DATE> to []NullDate", proto: listProto(dateProto(d1), dateProto(d2), nullProto()), protoType: listType(dateType()), want: []NullDate{{d1, true}, {d2, true}, {}}},
		{desc: "decode NULL to []NullDate", proto: nullProto(), protoType: listType(dateType()), want: []NullDate(nil)},
		// DATE ARRAY with []civil.Date
		{desc: "decode ARRAY<DATE> to []civil.Date", proto: listProto(dateProto(d1), dateProto(d2)), protoType: listType(dateType()), want: []civil.Date{d1, d2}},
		// DATE ARRAY with []NullDate
		{desc: "decode ARRAY<DATE> to []*civil.Date", proto: listProto(dateProto(d1), nullProto(), dateProto(d2)), protoType: listType(dateType()), want: []*civil.Date{&dValue, nil, &d2Value}},
		{desc: "decode NULL to []*civil.Date", proto: nullProto(), protoType: listType(dateType()), want: []*civil.Date(nil)},
		// STRUCT ARRAY
		// STRUCT schema is equal to the following Go struct:
		// type s struct {
		//     Col1 NullInt64
		//     Col2 []struct {
		//         SubCol1 float64
		//         SubCol2 string
		//     }
		// }
		{
			desc: "decode ARRAY<STRUCT> to []NullRow",
			proto: listProto(
				listProto(
					intProto(3),
					listProto(
						listProto(floatProto(3.14), stringProto("this")),
						listProto(floatProto(0.57), stringProto("siht")),
					),
				),
				listProto(
					nullProto(),
					nullProto(),
				),
				nullProto(),
			),
			protoType: listType(
				structType(
					mkField("Col1", intType()),
					mkField(
						"Col2",
						listType(
							structType(
								mkField("SubCol1", floatType()),
								mkField("SubCol2", stringType()),
							),
						),
					),
				),
			),
			want: []NullRow{
				{
					Row: Row{
						fields: []*sppb.StructType_Field{
							mkField("Col1", intType()),
							mkField(
								"Col2",
								listType(
									structType(
										mkField("SubCol1", floatType()),
										mkField("SubCol2", stringType()),
									),
								),
							),
						},
						vals: []*proto3.Value{
							intProto(3),
							listProto(
								listProto(floatProto(3.14), stringProto("this")),
								listProto(floatProto(0.57), stringProto("siht")),
							),
						},
					},
					Valid: true,
				},
				{
					Row: Row{
						fields: []*sppb.StructType_Field{
							mkField("Col1", intType()),
							mkField(
								"Col2",
								listType(
									structType(
										mkField("SubCol1", floatType()),
										mkField("SubCol2", stringType()),
									),
								),
							),
						},
						vals: []*proto3.Value{
							nullProto(),
							nullProto(),
						},
					},
					Valid: true,
				},
				{},
			},
		},
		{
			desc: "decode ARRAY<STRUCT> to []*struct",
			proto: listProto(
				listProto(
					intProto(3),
					listProto(
						listProto(floatProto(3.14), stringProto("this")),
						listProto(floatProto(0.57), stringProto("siht")),
					),
				),
				listProto(
					nullProto(),
					nullProto(),
				),
				nullProto(),
			),
			protoType: listType(
				structType(
					mkField("Col1", intType()),
					mkField(
						"Col2",
						listType(
							structType(
								mkField("SubCol1", floatType()),
								mkField("SubCol2", stringType()),
							),
						),
					),
				),
			),
			want: []*struct {
				Col1      NullInt64
				StructCol []*struct {
					SubCol1 NullFloat64
					SubCol2 string
				} `spanner:"Col2"`
			}{
				{
					Col1: NullInt64{3, true},
					StructCol: []*struct {
						SubCol1 NullFloat64
						SubCol2 string
					}{
						{
							SubCol1: NullFloat64{3.14, true},
							SubCol2: "this",
						},
						{
							SubCol1: NullFloat64{0.57, true},
							SubCol2: "siht",
						},
					},
				},
				{
					Col1: NullInt64{},
					StructCol: []*struct {
						SubCol1 NullFloat64
						SubCol2 string
					}(nil),
				},
				nil,
			},
		},
		// GenericColumnValue
		{desc: "decode STRING to GenericColumnValue", proto: stringProto("abc"), protoType: stringType(), want: GenericColumnValue{stringType(), stringProto("abc")}},
		{desc: "decode NULL to GenericColumnValue", proto: nullProto(), protoType: stringType(), want: GenericColumnValue{stringType(), nullProto()}},
		// not actually valid (stringProto inside int list), but demonstrates pass-through.
		{desc: "decode ARRAY<INT64> to GenericColumnValue", proto: listProto(intProto(5), nullProto(), stringProto("bcd")), protoType: listType(intType()), want: GenericColumnValue{Type: listType(intType()), Value: listProto(intProto(5), nullProto(), stringProto("bcd"))}},

		// Custom base types.
		{desc: "decode STRING to CustomString", proto: stringProto("bar"), protoType: stringType(), want: CustomString("bar")},
		{desc: "decode BYTES to CustomBytes", proto: bytesProto([]byte("ab")), protoType: bytesType(), want: CustomBytes("ab")},
		{desc: "decode INT64 to CustomInt64", proto: intProto(-100), protoType: intType(), want: CustomInt64(-100)},
		{desc: "decode BOOL to CustomBool", proto: boolProto(true), protoType: boolType(), want: CustomBool(true)},
		{desc: "decode FLOAT64 to CustomFloat64", proto: floatProto(6.626), protoType: floatType(), want: CustomFloat64(6.626)},
		{desc: "decode NUMERIC to CustomNumeric", proto: numericProto(numValuePtr), protoType: numericType(), want: CustomNumeric(*numValuePtr)},
		{desc: "decode TIMESTAMP to CustomTimestamp", proto: timeProto(t1), protoType: timeType(), want: CustomTime(t1)},
		{desc: "decode DATE to CustomDate", proto: dateProto(d1), protoType: dateType(), want: CustomDate(d1)},

		{desc: "decode NULL to CustomString", proto: nullProto(), protoType: stringType(), want: CustomString(""), wantErr: true},
		{desc: "decode NULL to CustomBytes", proto: nullProto(), protoType: bytesType(), want: CustomBytes(nil)},
		{desc: "decode NULL to CustomInt64", proto: nullProto(), protoType: intType(), want: CustomInt64(0), wantErr: true},
		{desc: "decode NULL to CustomBool", proto: nullProto(), protoType: boolType(), want: CustomBool(false), wantErr: true},
		{desc: "decode NULL to CustomFloat64", proto: nullProto(), protoType: floatType(), want: CustomFloat64(0), wantErr: true},
		{desc: "decode NULL to CustomNumeric", proto: nullProto(), protoType: numericType(), want: CustomNumeric{}, wantErr: true},
		{desc: "decode NULL to CustomTime", proto: nullProto(), protoType: timeType(), want: CustomTime{}, wantErr: true},
		{desc: "decode NULL to CustomDate", proto: nullProto(), protoType: dateType(), want: CustomDate{}, wantErr: true},

		{desc: "decode STRING to CustomNullString", proto: stringProto("bar"), protoType: stringType(), want: CustomNullString{"bar", true}},
		{desc: "decode INT64 to CustomNullInt64", proto: intProto(-100), protoType: intType(), want: CustomNullInt64{-100, true}},
		{desc: "decode BOOL to CustomNullBool", proto: boolProto(true), protoType: boolType(), want: CustomNullBool{true, true}},
		{desc: "decode FLOAT64 to CustomNullFloat64", proto: floatProto(6.626), protoType: floatType(), want: CustomNullFloat64{6.626, true}},
		{desc: "decode NUMERIC to CustomNullNumeric", proto: numericProto(numValuePtr), protoType: numericType(), want: CustomNullNumeric{*numValuePtr, true}},
		{desc: "decode TIMESTAMP to CustomNullTime", proto: timeProto(t1), protoType: timeType(), want: CustomNullTime{t1, true}},
		{desc: "decode DATE to CustomNullDate", proto: dateProto(d1), protoType: dateType(), want: CustomNullDate{d1, true}},

		{desc: "decode NULL to CustomNullString", proto: nullProto(), protoType: stringType(), want: CustomNullString{}},
		{desc: "decode NULL to CustomNullInt64", proto: nullProto(), protoType: intType(), want: CustomNullInt64{}},
		{desc: "decode NULL to CustomNullBool", proto: nullProto(), protoType: boolType(), want: CustomNullBool{}},
		{desc: "decode NULL to CustomNullFloat64", proto: nullProto(), protoType: floatType(), want: CustomNullFloat64{}},
		{desc: "decode NULL to CustomNullNumeric", proto: nullProto(), protoType: numericType(), want: CustomNullNumeric{}},
		{desc: "decode NULL to CustomNullTime", proto: nullProto(), protoType: timeType(), want: CustomNullTime{}},
		{desc: "decode NULL to CustomNullDate", proto: nullProto(), protoType: dateType(), want: CustomNullDate{}},

		// STRING ARRAY
		{desc: "decode NULL to []CustomString", proto: nullProto(), protoType: listType(stringType()), want: []CustomString(nil)},
		{desc: "decode ARRAY<STRING> to []CustomString", proto: listProto(stringProto("abc"), stringProto("bcd")), protoType: listType(stringType()), want: []CustomString{"abc", "bcd"}},
		{desc: "decode ARRAY<STRING> with NULL values to []CustomString", proto: listProto(stringProto("abc"), nullProto(), stringProto("bcd")), protoType: listType(stringType()), want: []CustomString{}, wantErr: true},
		{desc: "decode NULL to []CustomNullString", proto: nullProto(), protoType: listType(stringType()), want: []CustomNullString(nil)},
		{desc: "decode ARRAY<STRING> to []CustomNullString", proto: listProto(stringProto("abc"), nullProto(), stringProto("bcd")), protoType: listType(stringType()), want: []CustomNullString{{"abc", true}, {}, {"bcd", true}}},
		// BYTES ARRAY
		{desc: "decode NULL to []CustomBytes", proto: nullProto(), protoType: listType(bytesType()), want: []CustomBytes(nil)},
		{desc: "decode ARRAY<BYTES> to []CustomBytes", proto: listProto(bytesProto([]byte("abc")), nullProto(), bytesProto([]byte("bcd"))), protoType: listType(bytesType()), want: []CustomBytes{CustomBytes("abc"), CustomBytes(nil), CustomBytes("bcd")}},
		// INT64 ARRAY
		{desc: "decode NULL to []CustomInt64", proto: nullProto(), protoType: listType(intType()), want: []CustomInt64(nil)},
		{desc: "decode ARRAY<INT64> with NULL values to []CustomInt64", proto: listProto(intProto(-100), nullProto(), intProto(100)), protoType: listType(intType()), want: []CustomInt64{}, wantErr: true},
		{desc: "decode ARRAY<INT64> to []CustomInt64", proto: listProto(intProto(-100), intProto(100)), protoType: listType(intType()), want: []CustomInt64{-100, 100}},
		{desc: "decode NULL to []CustomNullInt64", proto: nullProto(), protoType: listType(intType()), want: []CustomNullInt64(nil)},
		{desc: "decode ARRAY<INT64> to []CustomNullInt64", proto: listProto(intProto(-100), nullProto(), intProto(100)), protoType: listType(intType()), want: []CustomNullInt64{{-100, true}, {}, {100, true}}},
		// BOOL ARRAY
		{desc: "decode NULL to []CustomBool", proto: nullProto(), protoType: listType(boolType()), want: []CustomBool(nil)},
		{desc: "decode ARRAY<BOOL> with NULL values to []CustomBool", proto: listProto(boolProto(false), nullProto(), boolProto(true)), protoType: listType(boolType()), want: []CustomBool{}, wantErr: true},
		{desc: "decode ARRAY<BOOL> to []CustomBool", proto: listProto(boolProto(false), boolProto(true)), protoType: listType(boolType()), want: []CustomBool{false, true}},
		{desc: "decode NULL to []CustomNullBool", proto: nullProto(), protoType: listType(boolType()), want: []CustomNullBool(nil)},
		{desc: "decode ARRAY<BOOL> to []CustomNullBool", proto: listProto(boolProto(false), nullProto(), boolProto(true)), protoType: listType(boolType()), want: []CustomNullBool{{false, true}, {}, {true, true}}},
		// FLOAT64 ARRAY
		{desc: "decode NULL to []CustomFloat64", proto: nullProto(), protoType: listType(floatType()), want: []CustomFloat64(nil)},
		{desc: "decode ARRAY<FLOAT64> with NULL values to []CustomFloat64", proto: listProto(floatProto(3.14), nullProto(), floatProto(6.626)), protoType: listType(floatType()), want: []CustomFloat64{}, wantErr: true},
		{desc: "decode ARRAY<FLOAT64> to []CustomFloat64", proto: listProto(floatProto(3.14), floatProto(6.626)), protoType: listType(floatType()), want: []CustomFloat64{3.14, 6.626}},
		{desc: "decode NULL to []CustomNullFloat64", proto: nullProto(), protoType: listType(floatType()), want: []CustomNullFloat64(nil)},
		{desc: "decode ARRAY<FLOAT64> to []CustomNullFloat64", proto: listProto(floatProto(3.14), nullProto(), floatProto(6.626)), protoType: listType(floatType()), want: []CustomNullFloat64{{3.14, true}, {}, {6.626, true}}},
		// NUMERIC ARRAY
		{desc: "decode NULL to []CustomNumeric", proto: nullProto(), protoType: listType(numericType()), want: []CustomNumeric(nil)},
		{desc: "decode ARRAY<NUMERIC> with NULL values to []CustomNumeric", proto: listProto(numericProto(numValuePtr), nullProto(), numericProto(num2ValuePtr)), protoType: listType(numericType()), want: []CustomNumeric{}, wantErr: true},
		{desc: "decode ARRAY<NUMERIC> to []CustomNumeric", proto: listProto(numericProto(numValuePtr), numericProto(num2ValuePtr)), protoType: listType(numericType()), want: []CustomNumeric{CustomNumeric(*numValuePtr), CustomNumeric(*num2ValuePtr)}},
		{desc: "decode NULL to []CustomNullNumeric", proto: nullProto(), protoType: listType(numericType()), want: []CustomNullNumeric(nil)},
		{desc: "decode ARRAY<NUMERIC> to []CustomNullNumeric", proto: listProto(numericProto(numValuePtr), nullProto(), numericProto(num2ValuePtr)), protoType: listType(numericType()), want: []CustomNullNumeric{{*numValuePtr, true}, {}, {*num2ValuePtr, true}}},
		// TIME ARRAY
		{desc: "decode NULL to []CustomTime", proto: nullProto(), protoType: listType(timeType()), want: []CustomTime(nil)},
		{desc: "decode ARRAY<TIMESTAMP> with NULL values to []CustomTime", proto: listProto(timeProto(t1), nullProto(), timeProto(t2)), protoType: listType(timeType()), want: []CustomTime{}, wantErr: true},
		{desc: "decode ARRAY<TIMESTAMP> to []CustomTime", proto: listProto(timeProto(t1), timeProto(t2)), protoType: listType(timeType()), want: []CustomTime{CustomTime(t1), CustomTime(t2)}},
		{desc: "decode NULL to []CustomNullTime", proto: nullProto(), protoType: listType(timeType()), want: []CustomNullTime(nil)},
		{desc: "decode ARRAY<TIMESTAMP> to []CustomNullTime", proto: listProto(timeProto(t1), nullProto(), timeProto(t2)), protoType: listType(timeType()), want: []CustomNullTime{{t1, true}, {}, {t2, true}}},
		// DATE ARRAY
		{desc: "decode NULL to []CustomDate", proto: nullProto(), protoType: listType(dateType()), want: []CustomDate(nil)},
		{desc: "decode ARRAY<DATE> with NULL values to []CustomDate", proto: listProto(dateProto(d1), nullProto(), dateProto(d2)), protoType: listType(dateType()), want: []CustomDate{}, wantErr: true},
		{desc: "decode ARRAY<DATE> to []CustomDate", proto: listProto(dateProto(d1), dateProto(d2)), protoType: listType(dateType()), want: []CustomDate{CustomDate(d1), CustomDate(d2)}},
		{desc: "decode NULL to []CustomNullDate", proto: nullProto(), protoType: listType(dateType()), want: []CustomNullDate(nil)},
		{desc: "decode ARRAY<DATE> to []CustomNullDate", proto: listProto(dateProto(d1), nullProto(), dateProto(d2)), protoType: listType(dateType()), want: []CustomNullDate{{d1, true}, {}, {d2, true}}},
		// CUSTOM STRUCT
		{desc: "decode STRING to CustomStructToString", proto: stringProto("A-B"), protoType: stringType(), want: customStructToString{"A", "B"}},
		{desc: "decode INT64 to CustomStructToInt", proto: intProto(123), protoType: intType(), want: customStructToInt{1, 23}},
		{desc: "decode FLOAT64 to CustomStructToFloat", proto: floatProto(123.123), protoType: floatType(), want: customStructToFloat{1.23, 12.3}},
		{desc: "decode BOOL to CustomStructToBool", proto: boolProto(true), protoType: boolType(), want: customStructToBool{true, false}},
		{desc: "decode BYTES to CustomStructToBytes", proto: bytesProto([]byte("AB")), protoType: bytesType(), want: customStructToBytes{[]byte("A"), []byte("B")}},
		{desc: "decode TIMESTAMP to CustomStructToTime", proto: timeProto(t1), protoType: timeType(), want: customStructToTime{"A", "B"}},
		{desc: "decode DATE to CustomStructToDate", proto: dateProto(d1), protoType: dateType(), want: customStructToDate{"A", "B"}},
	} {
		gotp := reflect.New(reflect.TypeOf(test.want))
		err := decodeValue(test.proto, test.protoType, gotp.Interface())
		if test.wantErr {
			if err == nil {
				t.Errorf("%s: missing expected decode failure for %v(%v)", test.desc, test.proto, test.protoType)
			}
			continue
		}
		if err != nil {
			t.Errorf("%s: cannot decode %v(%v): %v", test.desc, test.proto, test.protoType, err)
			continue
		}
		got := reflect.Indirect(gotp).Interface()
		if !testutil.Equal(got, test.want, cmp.AllowUnexported(CustomNumeric{}, CustomTime{}, CustomDate{}, Row{}, big.Rat{}, big.Int{})) {
			t.Errorf("%s: unexpected decoding result - got %v (%T), want %v (%T)", test.desc, got, got, test.want, test.want)
		}
	}
}

// Test error cases for decodeValue.
func TestDecodeValueErrors(t *testing.T) {
	var s string
	for i, test := range []struct {
		in *proto3.Value
		t  *sppb.Type
		v  interface{}
	}{
		{nullProto(), stringType(), nil},
		{nullProto(), stringType(), 1},
		{timeProto(t1), timeType(), &s},
	} {
		err := decodeValue(test.in, test.t, test.v)
		if err == nil {
			t.Errorf("#%d: want error, got nil", i)
		}
	}
}

func TestGetDecodableSpannerType(t *testing.T) {
	type CustomString string
	type CustomInt64 int64
	type CustomBool bool
	type CustomFloat64 float64
	type CustomTime time.Time
	type CustomDate civil.Date
	type CustomNumeric big.Rat

	type CustomNullString NullString
	type CustomNullInt64 NullInt64
	type CustomNullBool NullBool
	type CustomNullFloat64 NullFloat64
	type CustomNullTime NullTime
	type CustomNullDate NullDate
	type CustomNullNumeric NullNumeric

	type StringEmbedded struct {
		string
	}
	type NullStringEmbedded struct {
		NullString
	}

	for i, test := range []struct {
		in   interface{}
		want decodableSpannerType
	}{
		{"foo", spannerTypeNonNullString},
		{[]byte("ab"), spannerTypeByteArray},
		{[]byte(nil), spannerTypeByteArray},
		{int64(123), spannerTypeNonNullInt64},
		{true, spannerTypeNonNullBool},
		{3.14, spannerTypeNonNullFloat64},
		{time.Now(), spannerTypeNonNullTime},
		{civil.DateOf(time.Now()), spannerTypeNonNullDate},
		{NullString{}, spannerTypeNullString},
		{NullInt64{}, spannerTypeNullInt64},
		{NullBool{}, spannerTypeNullBool},
		{NullFloat64{}, spannerTypeNullFloat64},
		{NullTime{}, spannerTypeNullTime},
		{NullDate{}, spannerTypeNullDate},
		{*big.NewRat(1234, 1000), spannerTypeNonNullNumeric},
		{big.Rat{}, spannerTypeNonNullNumeric},
		{NullNumeric{}, spannerTypeNullNumeric},

		{[]string{"foo", "bar"}, spannerTypeArrayOfNonNullString},
		{[][]byte{{1, 2, 3}, {3, 2, 1}}, spannerTypeArrayOfByteArray},
		{[][]byte{}, spannerTypeArrayOfByteArray},
		{[]int64{int64(123)}, spannerTypeArrayOfNonNullInt64},
		{[]bool{true}, spannerTypeArrayOfNonNullBool},
		{[]float64{3.14}, spannerTypeArrayOfNonNullFloat64},
		{[]time.Time{time.Now()}, spannerTypeArrayOfNonNullTime},
		{[]civil.Date{civil.DateOf(time.Now())}, spannerTypeArrayOfNonNullDate},
		{[]NullString{}, spannerTypeArrayOfNullString},
		{[]NullInt64{}, spannerTypeArrayOfNullInt64},
		{[]NullBool{}, spannerTypeArrayOfNullBool},
		{[]NullFloat64{}, spannerTypeArrayOfNullFloat64},
		{[]NullTime{}, spannerTypeArrayOfNullTime},
		{[]NullDate{}, spannerTypeArrayOfNullDate},
		{[]big.Rat{}, spannerTypeArrayOfNonNullNumeric},
		{[]big.Rat{*big.NewRat(1234, 1000), *big.NewRat(1234, 100)}, spannerTypeArrayOfNonNullNumeric},
		{[]NullNumeric{}, spannerTypeArrayOfNullNumeric},

		{CustomString("foo"), spannerTypeNonNullString},
		{CustomInt64(-100), spannerTypeNonNullInt64},
		{CustomBool(true), spannerTypeNonNullBool},
		{CustomFloat64(3.141592), spannerTypeNonNullFloat64},
		{CustomTime(time.Now()), spannerTypeNonNullTime},
		{CustomDate(civil.DateOf(time.Now())), spannerTypeNonNullDate},
		{CustomNumeric(*big.NewRat(1234, 1000)), spannerTypeNonNullNumeric},

		{[]CustomString{}, spannerTypeArrayOfNonNullString},
		{[]CustomInt64{}, spannerTypeArrayOfNonNullInt64},
		{[]CustomBool{}, spannerTypeArrayOfNonNullBool},
		{[]CustomFloat64{}, spannerTypeArrayOfNonNullFloat64},
		{[]CustomTime{}, spannerTypeArrayOfNonNullTime},
		{[]CustomDate{}, spannerTypeArrayOfNonNullDate},
		{[]CustomNumeric{}, spannerTypeArrayOfNonNullNumeric},

		{CustomNullString{}, spannerTypeNullString},
		{CustomNullInt64{}, spannerTypeNullInt64},
		{CustomNullBool{}, spannerTypeNullBool},
		{CustomNullFloat64{}, spannerTypeNullFloat64},
		{CustomNullTime{}, spannerTypeNullTime},
		{CustomNullDate{}, spannerTypeNullDate},
		{CustomNullNumeric{}, spannerTypeNullNumeric},

		{[]CustomNullString{}, spannerTypeArrayOfNullString},
		{[]CustomNullInt64{}, spannerTypeArrayOfNullInt64},
		{[]CustomNullBool{}, spannerTypeArrayOfNullBool},
		{[]CustomNullFloat64{}, spannerTypeArrayOfNullFloat64},
		{[]CustomNullTime{}, spannerTypeArrayOfNullTime},
		{[]CustomNullDate{}, spannerTypeArrayOfNullDate},
		{[]CustomNullNumeric{}, spannerTypeArrayOfNullNumeric},

		{StringEmbedded{}, spannerTypeUnknown},
		{NullStringEmbedded{}, spannerTypeUnknown},
	} {
		// Pass a pointer to the original value.
		gotp := reflect.New(reflect.TypeOf(test.in))
		got := getDecodableSpannerType(gotp.Interface(), true)
		if got != test.want {
			t.Errorf("%d: unexpected decodable type from a pointer - got %v, want %v", i, got, test.want)
		}

		// Pass the original value.
		got = getDecodableSpannerType(test.in, false)
		if got != test.want {
			t.Errorf("%d: unexpected decodable type from a value - got %v, want %v", i, got, test.want)
		}
	}
}

// Test NaN encoding/decoding.
func TestNaN(t *testing.T) {
	// Decode NaN value.
	f := 0.0
	nf := NullFloat64{}
	// To float64
	if err := decodeValue(floatProto(math.NaN()), floatType(), &f); err != nil {
		t.Errorf("decodeValue returns %q for %v, want nil", err, floatProto(math.NaN()))
	}
	if !math.IsNaN(f) {
		t.Errorf("f = %v, want %v", f, math.NaN())
	}
	// To NullFloat64
	if err := decodeValue(floatProto(math.NaN()), floatType(), &nf); err != nil {
		t.Errorf("decodeValue returns %q for %v, want nil", err, floatProto(math.NaN()))
	}
	if !math.IsNaN(nf.Float64) || !nf.Valid {
		t.Errorf("f = %v, want %v", f, NullFloat64{math.NaN(), true})
	}
	// Encode NaN value
	// From float64
	v, _, err := encodeValue(math.NaN())
	if err != nil {
		t.Errorf("encodeValue returns %q for NaN, want nil", err)
	}
	x, ok := v.GetKind().(*proto3.Value_NumberValue)
	if !ok {
		t.Errorf("incorrect type for v.GetKind(): %T, want *proto3.Value_NumberValue", v.GetKind())
	}
	if !math.IsNaN(x.NumberValue) {
		t.Errorf("x.NumberValue = %v, want %v", x.NumberValue, math.NaN())
	}
	// From NullFloat64
	v, _, err = encodeValue(NullFloat64{math.NaN(), true})
	if err != nil {
		t.Errorf("encodeValue returns %q for NaN, want nil", err)
	}
	x, ok = v.GetKind().(*proto3.Value_NumberValue)
	if !ok {
		t.Errorf("incorrect type for v.GetKind(): %T, want *proto3.Value_NumberValue", v.GetKind())
	}
	if !math.IsNaN(x.NumberValue) {
		t.Errorf("x.NumberValue = %v, want %v", x.NumberValue, math.NaN())
	}
}

func TestGenericColumnValue(t *testing.T) {
	for _, test := range []struct {
		in   GenericColumnValue
		want interface{}
		fail bool
	}{
		{GenericColumnValue{stringType(), stringProto("abc")}, "abc", false},
		{GenericColumnValue{stringType(), stringProto("abc")}, 5, true},
		{GenericColumnValue{listType(intType()), listProto(intProto(91), nullProto(), intProto(87))}, []NullInt64{{91, true}, {}, {87, true}}, false},
		{GenericColumnValue{intType(), intProto(42)}, GenericColumnValue{intType(), intProto(42)}, false}, // trippy! :-)
	} {
		gotp := reflect.New(reflect.TypeOf(test.want))
		if err := test.in.Decode(gotp.Interface()); err != nil {
			if !test.fail {
				t.Errorf("cannot decode %v to %v: %v", test.in, test.want, err)
			}
			continue
		}
		if test.fail {
			t.Errorf("decoding %v to %v succeeds unexpectedly", test.in, test.want)
		}

		// Test we can go backwards as well.
		v, err := newGenericColumnValue(test.want)
		if err != nil {
			t.Errorf("NewGenericColumnValue failed: %v", err)
			continue
		}
		if !testEqual(*v, test.in) {
			t.Errorf("unexpected encode result - got %v, want %v", v, test.in)
		}
	}
}

func TestDecodeStruct(t *testing.T) {
	type CustomString string
	type CustomTime time.Time
	stype := &sppb.StructType{Fields: []*sppb.StructType_Field{
		{Name: "Id", Type: stringType()},
		{Name: "Time", Type: timeType()},
	}}
	lv := listValueProto(stringProto("id"), timeProto(t1))

	type (
		S1 struct {
			ID   string
			Time time.Time
		}
		S2 struct {
			ID   string
			Time string
		}
		S3 struct {
			ID   CustomString
			Time CustomTime
		}
		S4 struct {
			ID   CustomString
			Time CustomString
		}
		S5 struct {
			NullString
			Time CustomTime
		}
	)
	var (
		s1 S1
		s2 S2
		s3 S3
		s4 S4
		s5 S5
	)

	for _, test := range []struct {
		desc string
		ptr  interface{}
		want interface{}
		fail bool
	}{
		{
			desc: "decode to S1",
			ptr:  &s1,
			want: &S1{ID: "id", Time: t1},
		},
		{
			desc: "decode to S2",
			ptr:  &s2,
			fail: true,
		},
		{
			desc: "decode to S3",
			ptr:  &s3,
			want: &S3{ID: CustomString("id"), Time: CustomTime(t1)},
		},
		{
			desc: "decode to S4",
			ptr:  &s4,
			fail: true,
		},
		{
			desc: "decode to S5",
			ptr:  &s5,
			fail: true,
		},
	} {
		err := decodeStruct(stype, lv, test.ptr)
		if (err != nil) != test.fail {
			t.Errorf("%s: got error %v, wanted fail: %v", test.desc, err, test.fail)
		}
		if err == nil {
			if !testutil.Equal(test.ptr, test.want, cmp.AllowUnexported(CustomTime{})) {
				t.Errorf("%s: got %+v, want %+v", test.desc, test.ptr, test.want)
			}
		}
	}
}

func TestDecodeStructWithPointers(t *testing.T) {
	stype := &sppb.StructType{Fields: []*sppb.StructType_Field{
		{Name: "Str", Type: stringType()},
		{Name: "Int", Type: intType()},
		{Name: "Bool", Type: boolType()},
		{Name: "Float", Type: floatType()},
		{Name: "Time", Type: timeType()},
		{Name: "Date", Type: dateType()},
		{Name: "StrArray", Type: listType(stringType())},
		{Name: "IntArray", Type: listType(intType())},
		{Name: "BoolArray", Type: listType(boolType())},
		{Name: "FloatArray", Type: listType(floatType())},
		{Name: "TimeArray", Type: listType(timeType())},
		{Name: "DateArray", Type: listType(dateType())},
	}}
	lv := []*proto3.ListValue{
		listValueProto(
			stringProto("id"),
			intProto(15),
			boolProto(true),
			floatProto(3.14),
			timeProto(t1),
			dateProto(d1),
			listProto(stringProto("id1"), nullProto(), stringProto("id2")),
			listProto(intProto(16), nullProto(), intProto(17)),
			listProto(boolProto(true), nullProto(), boolProto(false)),
			listProto(floatProto(3.14), nullProto(), floatProto(6.626)),
			listProto(timeProto(t1), nullProto(), timeProto(t2)),
			listProto(dateProto(d1), nullProto(), dateProto(d2)),
		),
		listValueProto(
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
			nullProto(),
		),
	}

	type S1 struct {
		Str        *string
		Int        *int64
		Bool       *bool
		Float      *float64
		Time       *time.Time
		Date       *civil.Date
		StrArray   []*string
		IntArray   []*int64
		BoolArray  []*bool
		FloatArray []*float64
		TimeArray  []*time.Time
		DateArray  []*civil.Date
	}
	var s1 S1
	sValue := "id"
	iValue := int64(15)
	bValue := true
	fValue := 3.14
	tValue := t1
	dValue := d1
	sArrayValue1 := "id1"
	sArrayValue2 := "id2"
	sArrayValue := []*string{&sArrayValue1, nil, &sArrayValue2}
	iArrayValue1 := int64(16)
	iArrayValue2 := int64(17)
	iArrayValue := []*int64{&iArrayValue1, nil, &iArrayValue2}
	bArrayValue1 := true
	bArrayValue2 := false
	bArrayValue := []*bool{&bArrayValue1, nil, &bArrayValue2}
	f1Value := 3.14
	f2Value := 6.626
	fArrayValue := []*float64{&f1Value, nil, &f2Value}
	t1Value := t1
	t2Value := t2
	tArrayValue := []*time.Time{&t1Value, nil, &t2Value}
	d1Value := d1
	d2Value := d2
	dArrayValue := []*civil.Date{&d1Value, nil, &d2Value}

	for i, test := range []struct {
		desc string
		ptr  *S1
		want *S1
		fail bool
	}{
		{
			desc: "decode values to S1",
			ptr:  &s1,
			want: &S1{Str: &sValue, Int: &iValue, Bool: &bValue, Float: &fValue, Time: &tValue, Date: &dValue, StrArray: sArrayValue, IntArray: iArrayValue, BoolArray: bArrayValue, FloatArray: fArrayValue, TimeArray: tArrayValue, DateArray: dArrayValue},
		},
		{
			desc: "decode nulls to S1",
			ptr:  &s1,
			want: &S1{Str: nil, Int: nil, Bool: nil, Float: nil, Time: nil, Date: nil, StrArray: nil, IntArray: nil, BoolArray: nil, FloatArray: nil, TimeArray: nil, DateArray: nil},
		},
	} {
		err := decodeStruct(stype, lv[i], test.ptr)
		if (err != nil) != test.fail {
			t.Errorf("%s: got error %v, wanted fail: %v", test.desc, err, test.fail)
		}
		if err == nil {
			if !testutil.Equal(test.ptr, test.want) {
				t.Errorf("%s: got %+v, want %+v", test.desc, test.ptr, test.want)
			}
		}
	}
}

func TestEncodeStructValueDynamicStructs(t *testing.T) {
	dynStructType := reflect.StructOf([]reflect.StructField{
		{Name: "A", Type: reflect.TypeOf(0), Tag: `spanner:"a"`},
		{Name: "B", Type: reflect.TypeOf(""), Tag: `spanner:"b"`},
	})
	dynNullableStructType := reflect.PtrTo(dynStructType)
	dynStructArrType := reflect.SliceOf(dynStructType)
	dynNullableStructArrType := reflect.SliceOf(dynNullableStructType)

	dynStructValue := reflect.New(dynStructType)
	dynStructValue.Elem().Field(0).SetInt(10)
	dynStructValue.Elem().Field(1).SetString("abc")

	dynStructArrValue := reflect.MakeSlice(dynNullableStructArrType, 2, 2)
	dynStructArrValue.Index(0).Set(reflect.Zero(dynNullableStructType))
	dynStructArrValue.Index(1).Set(dynStructValue)

	structProtoType := structType(
		mkField("a", intType()),
		mkField("b", stringType()))

	arrProtoType := listType(structProtoType)

	for _, test := range []encodeTest{
		{
			"Dynanic non-NULL struct value.",
			dynStructValue.Elem().Interface(),
			listProto(intProto(10), stringProto("abc")),
			structProtoType,
		},
		{
			"Dynanic NULL struct value.",
			reflect.Zero(dynNullableStructType).Interface(),
			nullProto(),
			structProtoType,
		},
		{
			"Empty array of dynamic structs.",
			reflect.MakeSlice(dynStructArrType, 0, 0).Interface(),
			listProto([]*proto3.Value{}...),
			arrProtoType,
		},
		{
			"NULL array of non-NULL-able dynamic structs.",
			reflect.Zero(dynStructArrType).Interface(),
			nullProto(),
			arrProtoType,
		},
		{
			"NULL array of NULL-able(nil) dynamic structs.",
			reflect.Zero(dynNullableStructArrType).Interface(),
			nullProto(),
			arrProtoType,
		},
		{
			"Array containing NULL(nil) dynamic-typed struct elements.",
			dynStructArrValue.Interface(),
			listProto(
				nullProto(),
				listProto(intProto(10), stringProto("abc"))),
			arrProtoType,
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestEncodeStructValueEmptyStruct(t *testing.T) {
	emptyListValue := listProto([]*proto3.Value{}...)
	emptyStructType := structType([]*sppb.StructType_Field{}...)
	emptyStruct := struct{}{}
	nullEmptyStruct := (*struct{})(nil)

	dynamicEmptyStructType := reflect.StructOf(make([]reflect.StructField, 0, 0))
	dynamicStructArrType := reflect.SliceOf(reflect.PtrTo((dynamicEmptyStructType)))

	dynamicEmptyStruct := reflect.New(dynamicEmptyStructType)
	dynamicNullEmptyStruct := reflect.Zero(reflect.PtrTo(dynamicEmptyStructType))

	dynamicStructArrValue := reflect.MakeSlice(dynamicStructArrType, 2, 2)
	dynamicStructArrValue.Index(0).Set(dynamicNullEmptyStruct)
	dynamicStructArrValue.Index(1).Set(dynamicEmptyStruct)

	for _, test := range []encodeTest{
		{
			"Go empty struct.",
			emptyStruct,
			emptyListValue,
			emptyStructType,
		},
		{
			"Dynamic empty struct.",
			dynamicEmptyStruct.Interface(),
			emptyListValue,
			emptyStructType,
		},
		{
			"Go NULL empty struct.",
			nullEmptyStruct,
			nullProto(),
			emptyStructType,
		},
		{
			"Dynamic NULL empty struct.",
			dynamicNullEmptyStruct.Interface(),
			nullProto(),
			emptyStructType,
		},
		{
			"Non-empty array of dynamic NULL and non-NULL empty structs.",
			dynamicStructArrValue.Interface(),
			listProto(nullProto(), emptyListValue),
			listType(emptyStructType),
		},
		{
			"Non-empty array of nullable empty structs.",
			[]*struct{}{nullEmptyStruct, &emptyStruct},
			listProto(nullProto(), emptyListValue),
			listType(emptyStructType),
		},
		{
			"Empty array of empty struct.",
			[]struct{}{},
			emptyListValue,
			listType(emptyStructType),
		},
		{
			"Null array of empty structs.",
			[]struct{}(nil),
			nullProto(),
			listType(emptyStructType),
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestEncodeStructValueMixedStructTypes(t *testing.T) {
	type staticStruct struct {
		F int `spanner:"fStatic"`
	}
	s1 := staticStruct{10}
	s2 := (*staticStruct)(nil)

	var f float64
	dynStructType := reflect.StructOf([]reflect.StructField{
		{Name: "A", Type: reflect.TypeOf(f), Tag: `spanner:"fDynamic"`},
	})
	s3 := reflect.New(dynStructType)
	s3.Elem().Field(0).SetFloat(3.14)

	for _, test := range []encodeTest{
		{
			"'struct' with static and dynamic *struct, []*struct, []struct fields",
			struct {
				A []staticStruct
				B []*staticStruct
				C interface{}
			}{
				[]staticStruct{s1, s1},
				[]*staticStruct{&s1, s2},
				s3.Interface(),
			},
			listProto(
				listProto(listProto(intProto(10)), listProto(intProto(10))),
				listProto(listProto(intProto(10)), nullProto()),
				listProto(floatProto(3.14))),
			structType(
				mkField("A", listType(structType(mkField("fStatic", intType())))),
				mkField("B", listType(structType(mkField("fStatic", intType())))),
				mkField("C", structType(mkField("fDynamic", floatType())))),
		},
	} {
		encodeStructValue(test, t)
	}
}

func TestBindParamsDynamic(t *testing.T) {
	// Verify Statement.bindParams generates correct values and types.
	st := Statement{
		SQL:    "SELECT id from t_foo WHERE col = @var",
		Params: map[string]interface{}{"var": nil},
	}
	want := &sppb.ExecuteSqlRequest{
		Params: &proto3.Struct{
			Fields: map[string]*proto3.Value{"var": nil},
		},
		ParamTypes: map[string]*sppb.Type{"var": nil},
	}
	var (
		t1, _ = time.Parse(time.RFC3339Nano, "2016-11-15T15:04:05.999999999Z")
		// Boundaries
		t2, _ = time.Parse(time.RFC3339Nano, "0001-01-01T00:00:00.000000000Z")
	)
	dynamicStructType := reflect.StructOf([]reflect.StructField{
		{Name: "A", Type: reflect.TypeOf(t1), Tag: `spanner:"field"`},
		{Name: "B", Type: reflect.TypeOf(3.14), Tag: `spanner:""`},
	})
	dynamicStructArrType := reflect.SliceOf(reflect.PtrTo(dynamicStructType))
	dynamicEmptyStructType := reflect.StructOf(make([]reflect.StructField, 0, 0))

	dynamicStructTypeProto := structType(
		mkField("field", timeType()),
		mkField("", floatType()))

	s3 := reflect.New(dynamicStructType)
	s3.Elem().Field(0).Set(reflect.ValueOf(t1))
	s3.Elem().Field(1).SetFloat(1.4)

	s4 := reflect.New(dynamicStructType)
	s4.Elem().Field(0).Set(reflect.ValueOf(t2))
	s4.Elem().Field(1).SetFloat(-13.3)

	dynamicStructArrayVal := reflect.MakeSlice(dynamicStructArrType, 2, 2)
	dynamicStructArrayVal.Index(0).Set(s3)
	dynamicStructArrayVal.Index(1).Set(s4)

	for _, test := range []struct {
		val       interface{}
		wantField *proto3.Value
		wantType  *sppb.Type
	}{
		{
			s3.Interface(),
			listProto(timeProto(t1), floatProto(1.4)),
			structType(
				mkField("field", timeType()),
				mkField("", floatType())),
		},
		{
			reflect.Zero(reflect.PtrTo(dynamicEmptyStructType)).Interface(),
			nullProto(),
			structType([]*sppb.StructType_Field{}...),
		},
		{
			dynamicStructArrayVal.Interface(),
			listProto(
				listProto(timeProto(t1), floatProto(1.4)),
				listProto(timeProto(t2), floatProto(-13.3))),
			listType(dynamicStructTypeProto),
		},
		{
			[]*struct {
				F1 time.Time `spanner:"field"`
				F2 float64   `spanner:""`
			}{
				nil,
				{t1, 1.4},
			},
			listProto(
				nullProto(),
				listProto(timeProto(t1), floatProto(1.4))),
			listType(dynamicStructTypeProto),
		},
	} {
		st.Params["var"] = test.val
		want.Params.Fields["var"] = test.wantField
		want.ParamTypes["var"] = test.wantType
		gotParams, gotParamTypes, gotErr := st.convertParams()
		if gotErr != nil {
			t.Error(gotErr)
			continue
		}
		gotParamField := gotParams.Fields["var"]
		if !proto.Equal(gotParamField, test.wantField) {
			// handle NaN
			if test.wantType.Code == floatType().Code && proto.MarshalTextString(gotParamField) == proto.MarshalTextString(test.wantField) {
				continue
			}
			t.Errorf("%#v: got %v, want %v\n", test.val, gotParamField, test.wantField)
		}
		gotParamType := gotParamTypes["var"]
		if !proto.Equal(gotParamType, test.wantType) {
			t.Errorf("%#v: got %v, want %v\n", test.val, gotParamType, test.wantField)
		}
	}
}

// Test converting nullable types to json strings.
func TestJSONMarshal_NullTypes(t *testing.T) {
	type testcase struct {
		input  interface{}
		expect string
	}

	for _, test := range []struct {
		name  string
		cases []testcase
	}{
		{
			"NullString",
			[]testcase{
				{input: NullString{"this is a test string", true}, expect: `"this is a test string"`},
				{input: &NullString{"this is a test string", true}, expect: `"this is a test string"`},
				{input: &NullString{"this is a test string", false}, expect: "null"},
				{input: NullString{}, expect: "null"},
			},
		},
		{
			"NullInt64",
			[]testcase{
				{input: NullInt64{int64(123), true}, expect: "123"},
				{input: &NullInt64{int64(123), true}, expect: "123"},
				{input: &NullInt64{int64(123), false}, expect: "null"},
				{input: NullInt64{}, expect: "null"},
			},
		},
		{
			"NullFloat64",
			[]testcase{
				{input: NullFloat64{float64(123.123), true}, expect: "123.123"},
				{input: &NullFloat64{float64(123.123), true}, expect: "123.123"},
				{input: &NullFloat64{float64(123.123), false}, expect: "null"},
				{input: NullFloat64{}, expect: "null"},
			},
		},
		{
			"NullBool",
			[]testcase{
				{input: NullBool{true, true}, expect: "true"},
				{input: &NullBool{true, true}, expect: "true"},
				{input: &NullBool{true, false}, expect: "null"},
				{input: NullBool{}, expect: "null"},
			},
		},
		{
			"NullTime",
			[]testcase{
				{input: NullTime{time.Date(2009, 11, 17, 20, 34, 58, 651387237, time.UTC), true}, expect: `"2009-11-17T20:34:58.651387237Z"`},
				{input: &NullTime{time.Date(2009, 11, 17, 20, 34, 58, 651387237, time.UTC), true}, expect: `"2009-11-17T20:34:58.651387237Z"`},
				{input: &NullTime{time.Date(2009, 11, 17, 20, 34, 58, 651387237, time.UTC), false}, expect: "null"},
				{input: NullTime{}, expect: "null"},
			},
		},
		{
			"NullDate",
			[]testcase{
				{input: NullDate{civil.Date{Year: 2009, Month: time.November, Day: 17}, true}, expect: `"2009-11-17"`},
				{input: &NullDate{civil.Date{Year: 2009, Month: time.November, Day: 17}, true}, expect: `"2009-11-17"`},
				{input: &NullDate{civil.Date{Year: 2009, Month: time.November, Day: 17}, false}, expect: "null"},
				{input: NullDate{}, expect: "null"},
			},
		},
		{
			"NullNumeric",
			[]testcase{
				{input: NullNumeric{*big.NewRat(1234123456789, 1e9), true}, expect: `"1234.123456789"`},
				{input: &NullNumeric{*big.NewRat(1234123456789, 1e9), true}, expect: `"1234.123456789"`},
				{input: &NullNumeric{*big.NewRat(1234123456789, 1e9), false}, expect: "null"},
				{input: NullNumeric{}, expect: "null"},
			},
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			for _, tc := range test.cases {
				bytes, _ := json.Marshal(tc.input)
				got := string(bytes)
				if got != tc.expect {
					t.Fatalf("Incorrect marshalling to json strings: got %v, want %v", got, tc.expect)
				}
			}
		})
	}
}

// Test converting json strings to nullable types.
func TestJSONUnmarshal_NullTypes(t *testing.T) {
	type testcase struct {
		input       []byte
		got         interface{}
		isNull      bool
		expect      string
		expectError bool
	}

	for _, test := range []struct {
		name  string
		cases []testcase
	}{
		{
			"NullString",
			[]testcase{
				{input: []byte(`"this is a test string"`), got: NullString{}, isNull: false, expect: "this is a test string", expectError: false},
				{input: []byte(`""`), got: NullString{}, isNull: false, expect: "", expectError: false},
				{input: []byte("null"), got: NullString{}, isNull: true, expect: nullString, expectError: false},
				{input: nil, got: NullString{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(""), got: NullString{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(`"hello`), got: NullString{}, isNull: true, expect: nullString, expectError: true},
			},
		},
		{
			"NullInt64",
			[]testcase{
				{input: []byte("123"), got: NullInt64{}, isNull: false, expect: "123", expectError: false},
				{input: []byte("null"), got: NullInt64{}, isNull: true, expect: nullString, expectError: false},
				{input: nil, got: NullInt64{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(""), got: NullInt64{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(`"hello`), got: NullInt64{}, isNull: true, expect: nullString, expectError: true},
			},
		},
		{
			"NullFloat64",
			[]testcase{
				{input: []byte("123.123"), got: NullFloat64{}, isNull: false, expect: "123.123", expectError: false},
				{input: []byte("null"), got: NullFloat64{}, isNull: true, expect: nullString, expectError: false},
				{input: nil, got: NullFloat64{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(""), got: NullFloat64{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(`"hello`), got: NullFloat64{}, isNull: true, expect: nullString, expectError: true},
			},
		},
		{
			"NullBool",
			[]testcase{
				{input: []byte("true"), got: NullBool{}, isNull: false, expect: "true", expectError: false},
				{input: []byte("null"), got: NullBool{}, isNull: true, expect: nullString, expectError: false},
				{input: nil, got: NullBool{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(""), got: NullBool{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(`"hello`), got: NullBool{}, isNull: true, expect: nullString, expectError: true},
			},
		},
		{
			"NullTime",
			[]testcase{
				{input: []byte(`"2009-11-17T20:34:58.651387237Z"`), got: NullTime{}, isNull: false, expect: "2009-11-17T20:34:58.651387237Z", expectError: false},
				{input: []byte("null"), got: NullTime{}, isNull: true, expect: nullString, expectError: false},
				{input: nil, got: NullTime{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(""), got: NullTime{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(`"hello`), got: NullTime{}, isNull: true, expect: nullString, expectError: true},
			},
		},
		{
			"NullDate",
			[]testcase{
				{input: []byte(`"2009-11-17"`), got: NullDate{}, isNull: false, expect: "2009-11-17", expectError: false},
				{input: []byte("null"), got: NullDate{}, isNull: true, expect: nullString, expectError: false},
				{input: nil, got: NullDate{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(""), got: NullDate{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(`"hello`), got: NullDate{}, isNull: true, expect: nullString, expectError: true},
			},
		},
		{
			"NullNumeric",
			[]testcase{
				{input: []byte(`"1234.123456789"`), got: NullNumeric{}, isNull: false, expect: "1234.123456789", expectError: false},
				{input: []byte("null"), got: NullNumeric{}, isNull: true, expect: nullString, expectError: false},
				{input: nil, got: NullNumeric{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(""), got: NullNumeric{}, isNull: true, expect: nullString, expectError: true},
				{input: []byte(`"1234.123456789`), got: NullNumeric{}, isNull: true, expect: nullString, expectError: true},
			},
		},
	} {
		t.Run(test.name, func(t *testing.T) {
			for _, tc := range test.cases {
				switch v := tc.got.(type) {
				case NullString:
					err := json.Unmarshal(tc.input, &v)
					expectUnmarshalNullableTypes(t, err, v, tc.isNull, tc.expect, tc.expectError)
				case NullInt64:
					err := json.Unmarshal(tc.input, &v)
					expectUnmarshalNullableTypes(t, err, v, tc.isNull, tc.expect, tc.expectError)
				case NullFloat64:
					err := json.Unmarshal(tc.input, &v)
					expectUnmarshalNullableTypes(t, err, v, tc.isNull, tc.expect, tc.expectError)
				case NullBool:
					err := json.Unmarshal(tc.input, &v)
					expectUnmarshalNullableTypes(t, err, v, tc.isNull, tc.expect, tc.expectError)
				case NullTime:
					err := json.Unmarshal(tc.input, &v)
					expectUnmarshalNullableTypes(t, err, v, tc.isNull, tc.expect, tc.expectError)
				case NullDate:
					err := json.Unmarshal(tc.input, &v)
					expectUnmarshalNullableTypes(t, err, v, tc.isNull, tc.expect, tc.expectError)
				case NullNumeric:
					err := json.Unmarshal(tc.input, &v)
					expectUnmarshalNullableTypes(t, err, v, tc.isNull, tc.expect, tc.expectError)
				default:
					t.Fatalf("Unknown type: %T", v)
				}
			}
		})
	}
}

func expectUnmarshalNullableTypes(t *testing.T, err error, v interface{}, isNull bool, expect string, expectError bool) {
	if expectError {
		if err == nil {
			t.Fatalf("Expect to get an error, but got a nil")
		}
		return
	}

	if err != nil {
		t.Fatalf("Got an error when unmarshalling a valid json string: %q", err)
	}
	if s, ok := v.(NullableValue); !ok || s.IsNull() != isNull {
		t.Fatalf("Incorrect unmarshalling a json string to nullable types: got %q, want %q", v, expect)
	}
	if s, ok := v.(fmt.Stringer); !ok || s.String() != expect {
		t.Fatalf("Incorrect unmarshalling a json string to nullable types: got %q, want %q", v, expect)
	}
}