add unit tests for response_writer

headerforwarder/response_writer.go

@@ -23,6 +23,7 @@ import (
 // responses, and set on the rosetta response.
 type ResponseWriter struct {
 	writer               http.ResponseWriter
+	calledWriteHeaders   bool
 	RosettaRequestID     string
 	GetAdditionalHeaders func(string) (http.Header, bool)
 }
@@ -46,11 +47,16 @@ func (hfrw *ResponseWriter) Header() http.Header {
 
 // Write passes through to the underlying ResponseWriter instance
 func (hfrw *ResponseWriter) Write(b []byte) (int, error) {
+	if !hfrw.calledWriteHeaders {
+		hfrw.AddExtractedHeaders()
+	}
+
 	return hfrw.writer.Write(b)
 }
 
 // WriteHeader will add any final extracted headers, and then pass through to the underlying ResponseWriter instance
 func (hfrw *ResponseWriter) WriteHeader(statusCode int) {
+	hfrw.calledWriteHeaders = true
 	hfrw.AddExtractedHeaders()
 	hfrw.writer.WriteHeader(statusCode)
 }

headerforwarder/response_writer_test.go

@@ -0,0 +1,56 @@
+package headerforwarder
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func mockGetter(id string, headers http.Header) func(string) (http.Header, bool) {
+	return func(s string) (http.Header, bool) {
+		if s != id {
+			return nil, false
+		}
+
+		return headers, true
+	}
+}
+
+var mockHeader http.Header = http.Header{
+	"Test-Header": []string{"test-value"},
+}
+
+func TestWriteHeader(t *testing.T) {
+	writer := httptest.NewRecorder()
+	hfrw := NewResponseWriter(writer, "test-id", mockGetter("test-id", mockHeader))
+
+	hfrw.WriteHeader(200)
+
+	result := writer.Result()
+	assert.Equal(t, 200, result.StatusCode)
+}
+
+func TestWriteHeaderAddsHeaders(t *testing.T) {
+	writer := httptest.NewRecorder()
+	hfrw := NewResponseWriter(writer, "test-id", mockGetter("test-id", mockHeader))
+
+	hfrw.WriteHeader(200)
+
+	result := writer.Result()
+	assert.Equal(t, 200, result.StatusCode)
+	assert.Equal(t, mockHeader.Values("test-header"), result.Header.Values("test-header"))
+}
+
+// Tests that headers are written if Write is called before WriteHeader
+func TestWriteAddsHeaders(t *testing.T) {
+	writer := httptest.NewRecorder()
+	hfrw := NewResponseWriter(writer, "test-id", mockGetter("test-id", mockHeader))
+
+	hfrw.Write([]byte("test-bytes"))
+
+	result := writer.Result()
+	assert.Equal(t, 200, result.StatusCode)
+	assert.Equal(t, mockHeader.Values("test-header"), result.Header.Values("test-header"))
+}