Add test for multiple calls to Name().

Fixes #394

mux_test.go

@@ -1323,6 +1323,15 @@ func TestNamedRoutes(t *testing.T) {
 	}
 }
 
+func TestNameMultipleCalls(t *testing.T) {
+	r1 := NewRouter()
+	rt := r1.NewRoute().Name("foo").Name("bar")
+	err := rt.GetError()
+	if err == nil {
+		t.Errorf("Expected an error")
+	}
+}
+
 func TestStrictSlash(t *testing.T) {
 	r := NewRouter()
 	r.StrictSlash(true)