Add unit tests

router.go

@@ -353,7 +353,7 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 			}
 			err := route.handle(ctx)
 			if err != nil {
-				r.handleError(ctx, err)
+				r.HandleError(ctx, err)
 			}
 			r.putContext(ctx)
 			return
@@ -405,7 +405,7 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 			if r.MethodNotAllowed != nil {
 				r.MethodNotAllowed.ServeHTTP(w, req)
 			} else {
-				r.handleError(ctx, ErrMethodNotAllowed)
+				r.HandleError(ctx, ErrMethodNotAllowed)
 			}
 			return
 		}
@@ -415,11 +415,12 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	if r.NotFound != nil {
 		r.NotFound.ServeHTTP(w, req)
 	} else {
-		r.handleError(ctx, ErrNotFound)
+		r.HandleError(ctx, ErrNotFound)
 	}
 }
 
-func (r *Router) handleError(ctx *Context, err error) {
+// HandleError handles error.
+func (r *Router) HandleError(ctx *Context, err error) {
 	if r.ErrorHandler != nil {
 		r.ErrorHandler.Handle(ctx, err)
 		return

router_test.go

@@ -928,3 +928,56 @@ func ExampleRouter_ServeFiles() {
 	// such as "/favicon.ico".
 	router.NotFound = http.FileServer(http.Dir("public"))
 }
+
+type testErrorHandler struct {
+	status int
+}
+
+func (eh testErrorHandler) Handle(ctx *Context, err error) {
+	ctx.Error(err.Error(), eh.status)
+}
+
+func TestRouter_ErrorHandler(t *testing.T) {
+	router := NewRouter()
+	router.ErrorHandler = &testErrorHandler{http.StatusInternalServerError}
+	router.Get("/error/:msg", func(ctx *Context) error {
+		return errors.New(ctx.Params.String("msg"))
+	})
+
+	msgs := []string{"foo", "bar"}
+	for _, msg := range msgs {
+		w := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/error/"+msg, nil)
+		router.ServeHTTP(w, req)
+		if w.Body.String() != fmt.Sprintln(msg) {
+			t.Errorf("expected error body %q, got %q", fmt.Sprintln(msg), w.Body)
+		}
+		if w.Code != http.StatusInternalServerError {
+			t.Errorf("expected error status code %d, got %d", http.StatusInternalServerError, w.Code)
+		}
+	}
+}
+
+func TestRouter_HandleError(t *testing.T) {
+	router := NewRouter()
+	tests := []struct {
+		err  error
+		body string
+		code int
+	}{
+		{errors.New("foo"), "foo", http.StatusInternalServerError},
+		{ErrNotFound, ErrNotFound.Error(), ErrNotFound.Code},
+		{ErrMethodNotAllowed, ErrMethodNotAllowed.Error(), ErrMethodNotAllowed.Code},
+	}
+	for _, test := range tests {
+		w := httptest.NewRecorder()
+		ctx := newContext(w, nil)
+		router.HandleError(ctx, test.err)
+		if w.Body.String() != fmt.Sprintln(test.body) {
+			t.Errorf("expected error body %q, got %q", test.body, w.Body)
+		}
+		if w.Code != test.code {
+			t.Errorf("expected error status code %d, got %d", test.code, w.Code)
+		}
+	}
+}