Added direct piping test & buffering test (#410)

Signed-off-by: Francesco Guardiani <francescoguard@gmail.com>

v2/protocol/http/message_test.go

@@ -39,7 +39,7 @@ func TestNewMessageFromHttpRequest(t *testing.T) {
 				}
 
 				req := httptest.NewRequest("POST", "http://localhost", nil)
-				require.NoError(t, WriteRequest(ctx, (*binding.EventMessage)(&eventIn), req, binding.TransformerFactories{}))
+				require.NoError(t, WriteRequest(ctx, (*binding.EventMessage)(&eventIn), req))
 
 				got := NewMessageFromHttpRequest(req)
 				require.Equal(t, tt.encoding, got.ReadEncoding())

v2/protocol/http/write_responsewriter_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/cloudevents/sdk-go/v2/binding"
+	"github.com/cloudevents/sdk-go/v2/binding/buffering"
 	"github.com/cloudevents/sdk-go/v2/binding/test"
 	"github.com/cloudevents/sdk-go/v2/event"
 )
@@ -33,6 +34,54 @@ func TestWriteHttpResponseWriter(t *testing.T) {
 			messageFactory:   test.MustCreateMockBinaryMessage,
 			expectedEncoding: binding.EncodingBinary,
 		},
+		{
+			name:    "Structured to buffered to Structured",
+			context: context.TODO(),
+			messageFactory: func(e event.Event) binding.Message {
+				m := test.MustCreateMockStructuredMessage(e)
+
+				buffered, err := buffering.BufferMessage(context.TODO(), m)
+				require.NoError(t, err)
+
+				return buffered
+			},
+			expectedEncoding: binding.EncodingStructured,
+		},
+		{
+			name:    "Binary to buffered to Binary",
+			context: context.TODO(),
+			messageFactory: func(e event.Event) binding.Message {
+				m := test.MustCreateMockBinaryMessage(e)
+
+				buffered, err := buffering.BufferMessage(context.TODO(), m)
+				require.NoError(t, err)
+
+				return buffered
+			},
+			expectedEncoding: binding.EncodingBinary,
+		},
+		{
+			name:    "Direct structured HttpRequest to Structured",
+			context: context.TODO(),
+			messageFactory: func(e event.Event) binding.Message {
+				req := httptest.NewRequest("POST", "http://localhost", nil)
+				require.NoError(t, WriteRequest(binding.WithForceStructured(context.TODO()), binding.ToMessage(&e), req))
+
+				return NewMessageFromHttpRequest(req)
+			},
+			expectedEncoding: binding.EncodingStructured,
+		},
+		{
+			name:    "Binary to buffered to Binary",
+			context: context.TODO(),
+			messageFactory: func(e event.Event) binding.Message {
+				req := httptest.NewRequest("POST", "http://localhost", nil)
+				require.NoError(t, WriteRequest(binding.WithForceBinary(context.TODO()), binding.ToMessage(&e), req))
+
+				return NewMessageFromHttpRequest(req)
+			},
+			expectedEncoding: binding.EncodingBinary,
+		},
 		{
 			name:             "Event to Structured",
 			context:          binding.WithPreferredEventEncoding(context.TODO(), binding.EncodingStructured),