5 files changed, 219 insertions, 0 deletions
diff --git a/internal/testutil/exec.go b/internal/testutil/exec.go
new file mode 100644
index 00000000..eee1677b
--- /dev/null
+++ b/internal/testutil/exec.go
@@ -0,0 +1,46 @@
+// 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 (
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+// Exec executes "go test" on given helper with supplied environment variables.
+// It is useful to mock "os/exec" functions in tests. When succeeded, it returns
+// the result produced by the test helper.
+// The test helper should:
+//     1. Use WantHelperProcess function to determine if it is being called in helper mode.
+//     2. Call fmt.Fprintln(os.Stdout, ...) to print results for the main test to collect.
+func Exec(helper string, envs ...string) (string, error) {
+	cmd := exec.Command(os.Args[0], "-test.run="+helper, "--")
+	cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
+	cmd.Env = append(cmd.Env, envs...)
+	out, err := cmd.CombinedOutput()
+	str := string(out)
+	if err != nil {
+		return "", fmt.Errorf("%v - %s", err, str)
+	}
+
+	if strings.Contains(str, "no tests to run") {
+		return "", errors.New("no tests to run")
+	} else if !strings.Contains(str, "PASS") {
+		return "", errors.New(str)
+	}
+
+	// Collect helper result
+	result := str[:strings.Index(str, "PASS")]
+	result = strings.TrimSpace(result)
+	return result, nil
+}
+
+// WantHelperProcess returns true if current process is in helper mode.
+func WantHelperProcess() bool {
+	return os.Getenv("GO_WANT_HELPER_PROCESS") == "1"
+}
diff --git a/internal/testutil/exec_test.go b/internal/testutil/exec_test.go
new file mode 100644
index 00000000..679dc9d0
--- /dev/null
+++ b/internal/testutil/exec_test.go
@@ -0,0 +1,55 @@
+// 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 (
+	"errors"
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestExecHelper(t *testing.T) {
+	if !WantHelperProcess() {
+		return
+	}
+
+	if os.Getenv("PASS") != "1" {
+		fmt.Fprintln(os.Stdout, "tests failed")
+		os.Exit(1)
+	}
+
+	fmt.Fprintln(os.Stdout, "tests succeed")
+}
+
+func TestExec(t *testing.T) {
+	tests := []struct {
+		helper string
+		env    string
+		expOut string
+		expErr error
+	}{
+		{
+			helper: "NoTestsToRun",
+			expErr: errors.New("no tests to run"),
+		}, {
+			helper: "TestExecHelper",
+			expErr: errors.New("exit status 1 - tests failed\n"),
+		}, {
+			helper: "TestExecHelper",
+			env:    "PASS=1",
+			expOut: "tests succeed",
+		},
+	}
+	for _, test := range tests {
+		t.Run("", func(t *testing.T) {
+			out, err := Exec(test.helper, test.env)
+			assert.Equal(t, test.expErr, err)
+			assert.Equal(t, test.expOut, out)
+		})
+	}
+}
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
+	}
+}
diff --git a/internal/testutil/golden_test.go b/internal/testutil/golden_test.go
new file mode 100644
index 00000000..05f31399
--- /dev/null
+++ b/internal/testutil/golden_test.go
@@ -0,0 +1,52 @@
+// 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 (
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUpdate(t *testing.T) {
+	before := updateRegex
+	defer func() {
+		updateRegex = before
+	}()
+
+	t.Run("no flag", func(t *testing.T) {
+		updateRegex = nil
+		assert.False(t, Update("TestUpdate"))
+	})
+
+	tests := []struct {
+		regex string
+		name  string
+		want  bool
+	}{
+		{regex: "", name: "TestUpdate", want: false},
+		{regex: "TestNotFound", name: "TestUpdate", want: false},
+
+		{regex: ".*", name: "TestUpdate", want: true},
+	}
+	for _, test := range tests {
+		t.Run("", func(t *testing.T) {
+			updateRegex = &test.regex
+			assert.Equal(t, test.want, Update(test.name))
+		})
+	}
+}
+
+func TestAssertGolden(t *testing.T) {
+	// Make sure it does not blow up
+	AssertGolden(t, filepath.Join("testdata", "golden"), false, "{\n  \"Message\": \"This is a golden file.\"\n}")
+	AssertGolden(t, filepath.Join("testdata", "golden"), false, []byte("{\n  \"Message\": \"This is a golden file.\"\n}"))
+
+	type T struct {
+		Message string
+	}
+	AssertGolden(t, filepath.Join("testdata", "golden"), false, T{"This is a golden file."})
+}
diff --git a/internal/testutil/testdata/golden b/internal/testutil/testdata/golden
new file mode 100644
index 00000000..b0336818
--- /dev/null
+++ b/internal/testutil/testdata/golden
@@ -0,0 +1,3 @@
+{
+  "Message": "This is a golden file."
+}
+\ No newline at end of file