chore(server): add testing with healthz router. (#526)

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

gorush/server_test.go

@@ -353,7 +353,7 @@ func TestMetricsHandler(t *testing.T) {
 		})
 }
 
-func TestHeartbeatHandler(t *testing.T) {
+func TestGETHeartbeatHandler(t *testing.T) {
 	initTest()
 
 	r := gofight.New()
@@ -364,6 +364,17 @@ func TestHeartbeatHandler(t *testing.T) {
 		})
 }
 
+func TestHEADHeartbeatHandler(t *testing.T) {
+	initTest()
+
+	r := gofight.New()
+
+	r.HEAD("/healthz").
+		Run(routerEngine(), func(r gofight.HTTPResponse, rq gofight.HTTPRequest) {
+			assert.Equal(t, http.StatusOK, r.Code)
+		})
+}
+
 func TestVersionHandler(t *testing.T) {
 	SetVersion("3.0.0")
 	initTest()