1 files changed, 63 insertions, 0 deletions
diff --git a/internal/testutil/golden.go b/internal/testutil/golden.go
new file mode 100644
index 00000000..fa584d1b
--- /dev/null
+++ b/internal/testutil/golden.go
@@ -0,0 +1,63 @@
+// Copyright 2020 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package testutil
+
+import (
+	"encoding/json"
+	"flag"
+	"io/ioutil"
+	"regexp"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var updateRegex = flag.String("update", "", "Update testdata of tests matching the given regex")
+
+// Update returns true if update regex mathces given test name.
+func Update(name string) bool {
+	if updateRegex == nil || *updateRegex == "" {
+		return false
+	}
+	return regexp.MustCompile(*updateRegex).MatchString(name)
+}
+
+// AssertGolden compares what's got and what's in the golden file. It updates
+// the golden file on-demand.
+func AssertGolden(t testing.TB, path string, update bool, got interface{}) {
+	t.Helper()
+
+	data := marshal(t, got)
+
+	if update {
+		if err := ioutil.WriteFile(path, data, 0640); err != nil {
+			t.Fatalf("update golden file %q: %s", path, err)
+		}
+	}
+
+	golden, err := ioutil.ReadFile(path)
+	if err != nil {
+		t.Fatalf("read golden file %q: %s", path, err)
+	}
+
+	assert.Equal(t, string(golden), string(data))
+}
+
+func marshal(t testing.TB, v interface{}) []byte {
+	t.Helper()
+
+	switch v2 := v.(type) {
+	case string:
+		return []byte(v2)
+	case []byte:
+		return v2
+	default:
+		data, err := json.MarshalIndent(v, "", "  ")
+		if err != nil {
+			t.Fatal(err)
+		}
+		return data
+	}
+}