move lib/go/gremlin to ent/dialect (#1192)

Summary:
Pull Request resolved: https://github.com/facebookexternal/fbc/pull/1192

Pull Request resolved: https://github.com/facebookincubator/ent/pull/11

Reviewed By: alexsn

Differential Revision: D16377224

fbshipit-source-id: 07ca7436eb9b64fbe2299568560b91466b2417ba

dialect/gremlin/encoding/graphson/marshaler_test.go

@@ -0,0 +1,97 @@
+package graphson
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/json-iterator/go"
+	"github.com/modern-go/reflect2"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMarshalerEncode(t *testing.T) {
+	want := []byte(`{"@type": "g:Int32", "@value": 42}`)
+	m := &mocker{}
+	call := m.On("MarshalGraphson").Return(want, nil)
+	defer m.AssertExpectations(t)
+
+	tests := []interface{}{m, &m, func() *Marshaler { marshaler := Marshaler(m); return &marshaler }(), Marshaler(nil)}
+	call.Times(len(tests) - 1)
+
+	for _, tc := range tests {
+		tc := tc
+		t.Run(fmt.Sprintf("%T", tc), func(t *testing.T) {
+			got, err := Marshal(tc)
+			assert.NoError(t, err)
+			if !reflect2.IsNil(tc) {
+				assert.Equal(t, want, got)
+			} else {
+				assert.Equal(t, []byte("null"), got)
+			}
+		})
+	}
+}
+
+func TestMarshalerError(t *testing.T) {
+	errStr := "marshaler error"
+	m := &mocker{}
+	m.On("MarshalGraphson").Return(nil, errors.New(errStr)).Once()
+	defer m.AssertExpectations(t)
+
+	_, err := Marshal(m)
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), errStr)
+}
+
+func TestBadMarshaler(t *testing.T) {
+	m := &mocker{}
+	m.On("MarshalGraphson").Return([]byte(`{"@type": "g:Int32", "@value":`), nil).Once()
+	defer m.AssertExpectations(t)
+	_, err := Marshal(m)
+	assert.Error(t, err)
+}
+
+func TestUnmarshalerDecode(t *testing.T) {
+	data := `{"@type": "g:UUID", "@value": "cb682578-9d92-4499-9ebc-5c6aa73c5397"}`
+	var value string
+
+	m := &mocker{}
+	m.On("UnmarshalGraphson", mock.Anything).
+		Run(func(args mock.Arguments) {
+			data := args.Get(0).([]byte)
+			value = jsoniter.Get(data, "@value").ToString()
+		}).
+		Return(nil).
+		Once()
+	defer m.AssertExpectations(t)
+
+	err := UnmarshalFromString(data, m)
+	require.NoError(t, err)
+	assert.Equal(t, "cb682578-9d92-4499-9ebc-5c6aa73c5397", value)
+}
+
+func TestUnmarshalerError(t *testing.T) {
+	errStr := "unmarshaler error"
+	m := &mocker{}
+	m.On("UnmarshalGraphson", mock.Anything).Return(errors.New(errStr)).Once()
+	defer m.AssertExpectations(t)
+
+	err := Unmarshal([]byte(`{}`), m)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(),
+		fmt.Sprintf("graphson: error calling UnmarshalGraphson for type %s: %s",
+			reflect.TypeOf(m), errStr,
+		),
+	)
+}
+
+func TestUnmarshalBadInput(t *testing.T) {
+	m := &mocker{}
+	defer m.AssertExpectations(t)
+	err := UnmarshalFromString(`{"@type"}`, m)
+	assert.Error(t, err)
+}