mock: isolate objx-dependent code in their own source files

In order to ease maintenance of downstream forks of Testify that would
remove dependency on github.com/stretchr/objx we move all uses of that
module in isolated source files. A fork without that dependency could
just remove those files.
See #1752 (comment)

The use of objx is quite contained: it is only used in Mock.TestData().
Note that we can't just remove that method or change the return value because
that would be a breaking change.

Author: dolmen

mock/mock.go

@@ -13,7 +13,6 @@ import (
 
 	"github.com/davecgh/go-spew/spew"
 	"github.com/pmezard/go-difflib/difflib"
-	"github.com/stretchr/objx"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -311,7 +310,7 @@ type Mock struct {
 
 	// TestData holds any data that might be useful for testing.  Testify ignores
 	// this data completely allowing you to do whatever you like with it.
-	testData objx.Map
+	testData testData
 
 	mutex sync.Mutex
 }
@@ -324,16 +323,6 @@ func (m *Mock) String() string {
 	return fmt.Sprintf("%[1]T<%[1]p>", m)
 }
 
-// TestData holds any data that might be useful for testing.  Testify ignores
-// this data completely allowing you to do whatever you like with it.
-func (m *Mock) TestData() objx.Map {
-	if m.testData == nil {
-		m.testData = make(objx.Map)
-	}
-
-	return m.testData
-}
-
 /*
 	Setting expectations
 */

mock/mock_objx.go

@@ -0,0 +1,19 @@
+// This source file isolates the uses of the objx module to ease
+// maintenance of downstream forks that remove that dependency.
+// See https://github.com/stretchr/testify/issues/1752
+
+package mock
+
+import "github.com/stretchr/objx"
+
+type testData = objx.Map
+
+// TestData holds any data that might be useful for testing.  Testify ignores
+// this data completely allowing you to do whatever you like with it.
+func (m *Mock) TestData() objx.Map {
+	if m.testData == nil {
+		m.testData = make(objx.Map)
+	}
+
+	return m.testData
+}

mock/mock_objx_test.go

@@ -0,0 +1,18 @@
+package mock
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Mock_TestData(t *testing.T) {
+
+	var mockedService = new(TestExampleImplementation)
+
+	if assert.NotNil(t, mockedService.TestData()) {
+
+		mockedService.TestData().Set("something", 123)
+		assert.Equal(t, 123, mockedService.TestData().Get("something").Data())
+	}
+}

mock/mock_test.go

@@ -162,17 +162,6 @@ func (m *MockTestingT) FailNow() {
 	Mock
 */
 
-func Test_Mock_TestData(t *testing.T) {
-
-	var mockedService = new(TestExampleImplementation)
-
-	if assert.NotNil(t, mockedService.TestData()) {
-
-		mockedService.TestData().Set("something", 123)
-		assert.Equal(t, 123, mockedService.TestData().Get("something").Data())
-	}
-}
-
 func Test_Mock_On(t *testing.T) {
 
 	// make a test impl object