add content type checks to jsonhttp tests

pkg/jsonhttp/handlers_test.go

@@ -17,12 +17,15 @@ import (
 )
 
 func TestMethodHandler(t *testing.T) {
+	contentType := "application/swarm"
+
 	h := jsonhttp.MethodHandler{
 		"POST": http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			got, err := ioutil.ReadAll(r.Body)
 			if err != nil {
 				t.Fatal(err)
 			}
+			w.Header().Set("Content-Type", contentType)
 			fmt.Fprint(w, "got: ", string(got))
 		}),
 	}
@@ -46,6 +49,10 @@ func TestMethodHandler(t *testing.T) {
 		if gotBody != wantBody {
 			t.Errorf("got body %q, want %q", gotBody, wantBody)
 		}
+
+		if got := w.Header().Get("Content-Type"); got != contentType {
+			t.Errorf("got content type %q, want %q", got, contentType)
+		}
 	})
 
 	t.Run("method not allowed", func(t *testing.T) {
@@ -74,6 +81,8 @@ func TestMethodHandler(t *testing.T) {
 		if m.Message != wantMessage {
 			t.Errorf("got message message %q, want %q", m.Message, wantMessage)
 		}
+
+		testContentType(t, w)
 	})
 }
 
@@ -102,4 +111,6 @@ func TestNotFoundHandler(t *testing.T) {
 	if m.Message != wantMessage {
 		t.Errorf("got message message %q, want %q", m.Message, wantMessage)
 	}
+
+	testContentType(t, w)
 }

pkg/jsonhttp/jsonhttp_test.go

@@ -41,6 +41,8 @@ func TestRespond_defaults(t *testing.T) {
 	if m.Message != wantMessage {
 		t.Errorf("got message message %q, want %q", m.Message, wantMessage)
 	}
+
+	testContentType(t, w)
 }
 
 func TestRespond_statusResponse(t *testing.T) {
@@ -117,6 +119,8 @@ func TestRespond_statusResponse(t *testing.T) {
 		if m.Message != wantMessage {
 			t.Errorf("got message message %q, want %q", m.Message, wantMessage)
 		}
+
+		testContentType(t, w)
 	}
 }
 
@@ -187,6 +191,8 @@ func TestRespond_special(t *testing.T) {
 			if m.Message != tc.wantMessage {
 				t.Errorf("got message message %q, want %q", m.Message, tc.wantMessage)
 			}
+
+			testContentType(t, w)
 		})
 	}
 }
@@ -221,6 +227,8 @@ func TestRespond_custom(t *testing.T) {
 	if !reflect.DeepEqual(m, r) {
 		t.Errorf("got response %+v, want %+v", m, r)
 	}
+
+	testContentType(t, w)
 }
 
 func TestStandardHTTPResponds(t *testing.T) {
@@ -290,6 +298,8 @@ func TestStandardHTTPResponds(t *testing.T) {
 		if m.Message != http.StatusText(tc.code) {
 			t.Errorf("expected message message \"%s\", got \"%s\"", http.StatusText(tc.code), m.Message)
 		}
+
+		testContentType(t, w)
 	}
 }
 
@@ -307,3 +317,11 @@ func TestPanicRespond(t *testing.T) {
 		true: "",
 	})
 }
+
+func testContentType(t *testing.T, r *httptest.ResponseRecorder) {
+	t.Helper()
+
+	if got := r.Header().Get("Content-Type"); got != jsonhttp.DefaultContentTypeHeader {
+		t.Errorf("got content type %q, want %q", got, jsonhttp.DefaultContentTypeHeader)
+	}
+}