feat(spanner): add support for NUMERIC data type (#2415)

* spanner: add support for NUMERIC data type
* Add integration test for Numeric support.

spanner/cmp_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package spanner
 
 import (
+	"math/big"
 	"strings"
 
 	"cloud.google.com/go/internal/testutil"
@@ -27,7 +28,7 @@ import (
 func testEqual(a, b interface{}) bool {
 	return testutil.Equal(a, b,
 		cmp.AllowUnexported(TimestampBound{}, Error{}, TransactionOutcomeUnknownError{},
-			Mutation{}, Row{}, Partition{}, BatchReadOnlyTransactionID{}),
+			Mutation{}, Row{}, Partition{}, BatchReadOnlyTransactionID{}, big.Rat{}, big.Int{}),
 		cmp.FilterPath(func(path cmp.Path) bool {
 			// Ignore Error.state, Error.sizeCache, and Error.unknownFields
 			if strings.HasSuffix(path.GoString(), ".err.(*status.Error).state") {

spanner/integration_test.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"log"
 	"math"
+	"math/big"
 	"os"
 	"reflect"
 	"regexp"
@@ -1318,7 +1319,44 @@ func TestIntegration_BasicTypes(t *testing.T) {
 
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
 	defer cancel()
-	client, _, cleanup := prepareIntegrationTest(ctx, t, DefaultSessionPoolConfig, singerDBStatements)
+	stmts := singerDBStatements
+	if !isEmulatorEnvSet() {
+		stmts = []string{
+			`CREATE TABLE Singers (
+					SingerId	INT64 NOT NULL,
+					FirstName	STRING(1024),
+					LastName	STRING(1024),
+					SingerInfo	BYTES(MAX)
+				) PRIMARY KEY (SingerId)`,
+			`CREATE INDEX SingerByName ON Singers(FirstName, LastName)`,
+			`CREATE TABLE Accounts (
+					AccountId	INT64 NOT NULL,
+					Nickname	STRING(100),
+					Balance		INT64 NOT NULL,
+				) PRIMARY KEY (AccountId)`,
+			`CREATE INDEX AccountByNickname ON Accounts(Nickname) STORING (Balance)`,
+			`CREATE TABLE Types (
+					RowID		INT64 NOT NULL,
+					String		STRING(MAX),
+					StringArray	ARRAY<STRING(MAX)>,
+					Bytes		BYTES(MAX),
+					BytesArray	ARRAY<BYTES(MAX)>,
+					Int64a		INT64,
+					Int64Array	ARRAY<INT64>,
+					Bool		BOOL,
+					BoolArray	ARRAY<BOOL>,
+					Float64		FLOAT64,
+					Float64Array	ARRAY<FLOAT64>,
+					Date		DATE,
+					DateArray	ARRAY<DATE>,
+					Timestamp	TIMESTAMP,
+					TimestampArray	ARRAY<TIMESTAMP>,
+					Numeric		NUMERIC,
+					NumericArray	ARRAY<NUMERIC>
+				) PRIMARY KEY (RowID)`,
+		}
+	}
+	client, _, cleanup := prepareIntegrationTest(ctx, t, DefaultSessionPoolConfig, stmts)
 	defer cleanup()
 
 	t1, _ := time.Parse(time.RFC3339Nano, "2016-11-15T15:04:05.999999999Z")
@@ -1330,6 +1368,10 @@ func TestIntegration_BasicTypes(t *testing.T) {
 	d2, _ := civil.ParseDate("0001-01-01")
 	d3, _ := civil.ParseDate("9999-12-31")
 
+	n0 := big.Rat{}
+	n1 := *big.NewRat(123456789, 1)
+	n2 := *big.NewRat(123456789, 1000000000)
+
 	tests := []struct {
 		col  string
 		val  interface{}
@@ -1420,6 +1462,31 @@ func TestIntegration_BasicTypes(t *testing.T) {
 		{col: "TimestampArray", val: []time.Time{t1, t2, t3}, want: []NullTime{{t1, true}, {t2, true}, {t3, true}}},
 	}
 
+	if !isEmulatorEnvSet() {
+		for _, tc := range []struct {
+			col  string
+			val  interface{}
+			want interface{}
+		}{
+			{col: "Numeric", val: n1},
+			{col: "Numeric", val: n2},
+			{col: "Numeric", val: n1, want: NullNumeric{n1, true}},
+			{col: "Numeric", val: n2, want: NullNumeric{n2, true}},
+			{col: "Numeric", val: NullNumeric{n1, true}, want: n1},
+			{col: "Numeric", val: NullNumeric{n1, true}, want: NullNumeric{n1, true}},
+			{col: "Numeric", val: NullNumeric{n0, false}},
+			{col: "Numeric", val: nil, want: NullNumeric{}},
+			{col: "NumericArray", val: []big.Rat(nil), want: []NullNumeric(nil)},
+			{col: "NumericArray", val: []big.Rat{}, want: []NullNumeric{}},
+			{col: "NumericArray", val: []big.Rat{n1, n2}, want: []NullNumeric{{n1, true}, {n2, true}}},
+			{col: "NumericArray", val: []NullNumeric(nil)},
+			{col: "NumericArray", val: []NullNumeric{}},
+			{col: "NumericArray", val: []NullNumeric{{n1, true}, {n2, true}, {}}},
+		} {
+			tests = append(tests, tc)
+		}
+	}
+
 	// Write rows into table first.
 	var muts []*Mutation
 	for i, test := range tests {
@@ -3124,8 +3191,12 @@ func maxDuration(a, b time.Duration) time.Duration {
 	return b
 }
 
+func isEmulatorEnvSet() bool {
+	return os.Getenv("SPANNER_EMULATOR_HOST") != ""
+}
+
 func skipEmulatorTest(t *testing.T) {
-	if os.Getenv("SPANNER_EMULATOR_HOST") != "" {
+	if isEmulatorEnvSet() {
 		t.Skip("Skipping testing against the emulator.")
 	}
 }

spanner/protoutils.go

@@ -18,6 +18,7 @@ package spanner
 
 import (
 	"encoding/base64"
+	"math/big"
 	"strconv"
 	"time"
 
@@ -64,6 +65,14 @@ func floatType() *sppb.Type {
 	return &sppb.Type{Code: sppb.TypeCode_FLOAT64}
 }
 
+func numericProto(n *big.Rat) *proto3.Value {
+	return &proto3.Value{Kind: &proto3.Value_StringValue{StringValue: NumericString(n)}}
+}
+
+func numericType() *sppb.Type {
+	return &sppb.Type{Code: sppb.TypeCode_NUMERIC}
+}
+
 func bytesProto(b []byte) *proto3.Value {
 	return &proto3.Value{Kind: &proto3.Value_StringValue{StringValue: base64.StdEncoding.EncodeToString(b)}}
 }

spanner/row_test.go

@@ -745,7 +745,7 @@ func TestBrokenRow(t *testing.T) {
 				[]*proto3.Value{stringProto("nan")},
 			},
 			&NullFloat64{},
-			errDecodeColumn(0, errUnexpectedNumStr("nan")),
+			errDecodeColumn(0, errUnexpectedFloat64Str("nan")),
 		},
 		{
 			// Field specifies FLOAT64 type, but value is wrongly encoded.
@@ -756,7 +756,7 @@ func TestBrokenRow(t *testing.T) {
 				[]*proto3.Value{stringProto("nan")},
 			},
 			proto.Float64(0),
-			errDecodeColumn(0, errUnexpectedNumStr("nan")),
+			errDecodeColumn(0, errUnexpectedFloat64Str("nan")),
 		},
 		{
 			// Field specifies BYTES type, value is having a nil Kind.