Merge pull request #1263 from ydb-platform/cast-to-test

added test for internal/value.CastTo()

Author: asmyasnikov

internal/value/cast.go

@@ -1,5 +1,14 @@
 package value
 
 func CastTo(v Value, dst interface{}) error {
+	if dst == nil {
+		return errNilDestination
+	}
+	if ptr, has := dst.(*Value); has {
+		*ptr = v
+
+		return nil
+	}
+
 	return v.castTo(dst)
 }

internal/value/cast_test.go

@@ -0,0 +1,141 @@
+package value
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/ydb-platform/ydb-go-sdk/v3/internal/xtest"
+)
+
+func ptr[T any]() interface{} {
+	var zeroValue T
+
+	return &zeroValue
+}
+
+func value2ptr[T any](v T) *T {
+	return &v
+}
+
+func unwrapPtr(v interface{}) interface{} {
+	return reflect.ValueOf(v).Elem().Interface()
+}
+
+func TestCastTo(t *testing.T) {
+	for _, tt := range []struct {
+		name  string
+		value Value
+		dst   interface{}
+		exp   interface{}
+		err   error
+	}{
+		{
+			name:  xtest.CurrentFileLine(),
+			value: TextValue("test"),
+			dst:   (interface{})(nil),
+			err:   errNilDestination,
+		},
+
+		{
+			name:  xtest.CurrentFileLine(),
+			value: TextValue("test"),
+			dst:   ptr[Value](),
+			exp:   TextValue("test"),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: OptionalValue(TextValue("test")),
+			dst:   ptr[Value](),
+			exp:   OptionalValue(TextValue("test")),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: TextValue("test"),
+			dst:   ptr[string](),
+			exp:   "test",
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: OptionalValue(TextValue("test")),
+			dst:   ptr[*string](),
+			exp:   value2ptr("test"),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: TextValue("test"),
+			dst:   ptr[[]byte](),
+			exp:   []byte("test"),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: OptionalValue(TextValue("test")),
+			dst:   ptr[*[]byte](),
+			exp:   value2ptr([]byte("test")),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: TextValue("test"),
+			dst:   ptr[[]byte](),
+			exp:   []byte("test"),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: TextValue("test"),
+			dst:   ptr[int](),
+			err:   ErrCannotCast,
+		},
+
+		{
+			name:  xtest.CurrentFileLine(),
+			value: BytesValue([]byte("test")),
+			dst:   ptr[Value](),
+			exp:   BytesValue([]byte("test")),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: BytesValue([]byte("test")),
+			dst:   ptr[string](),
+			exp:   "test",
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: BytesValue([]byte("test")),
+			dst:   ptr[[]byte](),
+			exp:   []byte("test"),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: BytesValue([]byte("test")),
+			dst:   ptr[[]byte](),
+			exp:   []byte("test"),
+			err:   nil,
+		},
+		{
+			name:  xtest.CurrentFileLine(),
+			value: BytesValue([]byte("test")),
+			dst:   ptr[int](),
+			err:   ErrCannotCast,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.err == nil {
+				require.NoError(t, CastTo(tt.value, tt.dst))
+				require.Equal(t, tt.exp, unwrapPtr(tt.dst))
+			} else {
+				require.ErrorIs(t, CastTo(tt.value, tt.dst), tt.err)
+			}
+		})
+	}
+}

internal/value/errors.go

@@ -5,4 +5,5 @@ import "errors"
 var (
 	ErrCannotCast                   = errors.New("cannot cast")
 	errDestinationTypeIsNotAPointer = errors.New("destination type is not a pointer")
+	errNilDestination               = errors.New("destination is nil")
 )