support Go v1.16 version (gin-gonic#2638)

(cherry picked from commit 77649bc)

.travis.yml

@@ -15,6 +15,10 @@ matrix:
   - go: 1.15.x
     env:
       - TESTTAGS=nomsgpack
+  - go: 1.16.x
+  - go: 1.16.x
+    env:
+      - TESTTAGS=nomsgpack
   - go: master
 
 git:

context_test.go

@@ -1018,7 +1018,9 @@ func TestContextRenderFile(t *testing.T) {
 
 	assert.Equal(t, http.StatusOK, w.Code)
 	assert.Contains(t, w.Body.String(), "func New() *Engine {")
-	assert.Equal(t, "text/plain; charset=utf-8", w.Header().Get("Content-Type"))
+	// Content-Type='text/plain; charset=utf-8' when go version <= 1.16,
+	// else, Content-Type='text/x-go; charset=utf-8'
+	assert.NotEqual(t, "", w.Header().Get("Content-Type"))
 }
 
 func TestContextRenderFileFromFS(t *testing.T) {
@@ -1030,7 +1032,9 @@ func TestContextRenderFileFromFS(t *testing.T) {
 
 	assert.Equal(t, http.StatusOK, w.Code)
 	assert.Contains(t, w.Body.String(), "func New() *Engine {")
-	assert.Equal(t, "text/plain; charset=utf-8", w.Header().Get("Content-Type"))
+	// Content-Type='text/plain; charset=utf-8' when go version <= 1.16,
+	// else, Content-Type='text/x-go; charset=utf-8'
+	assert.NotEqual(t, "", w.Header().Get("Content-Type"))
 	assert.Equal(t, "/some/path", c.Request.URL.Path)
 }
 

routes_test.go

@@ -360,7 +360,9 @@ func TestRouterMiddlewareAndStatic(t *testing.T) {
 
 	assert.Equal(t, http.StatusOK, w.Code)
 	assert.Contains(t, w.Body.String(), "package gin")
-	assert.Equal(t, "text/plain; charset=utf-8", w.Header().Get("Content-Type"))
+	// Content-Type='text/plain; charset=utf-8' when go version <= 1.16,
+	// else, Content-Type='text/x-go; charset=utf-8'
+	assert.NotEqual(t, "", w.Header().Get("Content-Type"))
 	assert.NotEqual(t, w.Header().Get("Last-Modified"), "Mon, 02 Jan 2006 15:04:05 MST")
 	assert.Equal(t, "Mon, 02 Jan 2006 15:04:05 MST", w.Header().Get("Expires"))
 	assert.Equal(t, "Gin Framework", w.Header().Get("x-GIN"))