add FuncMap testing

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

fixtures/basic/raw.tmpl

@@ -0,0 +1 @@
+Date: {[{.now | formatAsDate}]}

gin_test.go

@@ -6,6 +6,7 @@ package gin
 
 import (
 	"fmt"
+	"html/template"
 	"io/ioutil"
 	"net/http"
 	"reflect"
@@ -15,6 +16,11 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func formatAsDate(t time.Time) string {
+	year, month, day := t.Date()
+	return fmt.Sprintf("%d/%02d/%02d", year, month, day)
+}
+
 func setupHTMLFiles(t *testing.T) func() {
 	go func() {
 		router := New()
@@ -32,12 +38,21 @@ func setupHTMLFiles(t *testing.T) func() {
 
 func setupHTMLGlob(t *testing.T) func() {
 	go func() {
+		SetMode(DebugMode)
 		router := New()
 		router.Delims("{[{", "}]}")
+		router.SetFuncMap(template.FuncMap{
+			"formatAsDate": formatAsDate,
+		})
 		router.LoadHTMLGlob("./fixtures/basic/*")
 		router.GET("/test", func(c *Context) {
 			c.HTML(http.StatusOK, "hello.tmpl", map[string]string{"name": "world"})
 		})
+		router.GET("/raw", func(c *Context) {
+			c.HTML(http.StatusOK, "raw.tmpl", map[string]interface{}{
+				"now": time.Date(2017, 07, 01, 0, 0, 0, 0, time.UTC),
+			})
+		})
 		router.Run(":8888")
 	}()
 	t.Log("waiting 1 second for server startup")
@@ -59,6 +74,20 @@ func TestLoadHTMLGlob(t *testing.T) {
 	td()
 }
 
+func TestLoadHTMLFromFuncMap(t *testing.T) {
+	time.Now()
+	td := setupHTMLGlob(t)
+	res, err := http.Get("http://127.0.0.1:8888/raw")
+	if err != nil {
+		fmt.Println(err)
+	}
+
+	resp, _ := ioutil.ReadAll(res.Body)
+	assert.Equal(t, "Date: 2017/07/01\n", string(resp[:]))
+
+	td()
+}
+
 // func (engine *Engine) LoadHTMLFiles(files ...string) {
 // func (engine *Engine) RunTLS(addr string, cert string, key string) error {