Ensure the instrumentedResponseWriter correctly sets the http

status in the context.

Signed-off-by: Richard Scothern <richard.scothern@gmail.com>

context/http.go

@@ -322,9 +322,7 @@ func (irw *instrumentedResponseWriter) Value(key interface{}) interface{} {
 		case "written":
 			return irw.written
 		case "status":
-			if irw.status != 0 {
-				return irw.status
-			}
+			return irw.status
 		case "contenttype":
 			contentType := irw.Header().Get("Content-Type")
 			if contentType != "" {

context/http_test.go

@@ -145,6 +145,10 @@ func TestWithResponseWriter(t *testing.T) {
 		t.Fatalf("unexpected response writer returned: %#v != %#v", grw, rw)
 	}
 
+	if ctx.Value("http.response.status") != 0 {
+		t.Fatalf("response status should always be a number and should be zero here: %v != 0", ctx.Value("http.response.status"))
+	}
+
 	if n, err := rw.Write(make([]byte, 1024)); err != nil {
 		t.Fatalf("unexpected error writing: %v", err)
 	} else if n != 1024 {

registry/handlers/api_test.go

@@ -93,7 +93,7 @@ func TestURLPrefix(t *testing.T) {
 
 }
 
-// TestLayerAPI conducts a full of the of the layer api.
+// TestLayerAPI conducts a full test of the of the layer api.
 func TestLayerAPI(t *testing.T) {
 	// TODO(stevvooe): This test code is complete junk but it should cover the
 	// complete flow. This must be broken down and checked against the
@@ -246,6 +246,16 @@ func TestLayerAPI(t *testing.T) {
 		t.Fatalf("response body did not pass verification")
 	}
 
+	// ----------------
+	// Fetch the layer with an invalid digest
+	badURL := strings.Replace(layerURL, "tarsum", "trsum", 1)
+	resp, err = http.Get(badURL)
+	if err != nil {
+		t.Fatalf("unexpected error fetching layer: %v", err)
+	}
+
+	checkResponse(t, "fetching layer bad digest", resp, http.StatusBadRequest)
+
 	// Missing tests:
 	// 	- Upload the same tarsum file under and different repository and
 	//       ensure the content remains uncorrupted.