Add test.Helper, also works with Go 1.8

internal/fs/helpers.go

@@ -3,6 +3,8 @@ package fs
 import (
 	"os"
 	"testing"
+
+	"github.com/restic/restic/internal/test"
 )
 
 // IsRegularFile returns true if fi belongs to a normal file. If fi is nil,
@@ -17,6 +19,8 @@ func IsRegularFile(fi os.FileInfo) bool {
 
 // TestChdir changes the current directory to dest, the function back returns to the previous directory.
 func TestChdir(t testing.TB, dest string) (back func()) {
+	test.Helper(t).Helper()
+
 	prev, err := os.Getwd()
 	if err != nil {
 		t.Fatal(err)
@@ -29,6 +33,7 @@ func TestChdir(t testing.TB, dest string) (back func()) {
 	}
 
 	return func() {
+		test.Helper(t).Helper()
 		t.Logf("chdir back to %v", prev)
 		err = os.Chdir(prev)
 		if err != nil {

internal/repository/testing.go

@@ -42,6 +42,7 @@ const testChunkerPol = chunker.Pol(0x3DA3358B4DC173)
 // password. If be is nil, an in-memory backend is used. A constant polynomial
 // is used for the chunker and low-security test parameters.
 func TestRepositoryWithBackend(t testing.TB, be restic.Backend) (r restic.Repository, cleanup func()) {
+	test.Helper(t).Helper()
 	TestUseLowSecurityKDFParameters(t)
 	restic.TestDisableCheckPolynomial(t)
 
@@ -70,6 +71,7 @@ func TestRepositoryWithBackend(t testing.TB, be restic.Backend) (r restic.Reposi
 // a non-existing directory, a local backend is created there and this is used
 // instead. The directory is not removed, but left there for inspection.
 func TestRepository(t testing.TB) (r restic.Repository, cleanup func()) {
+	test.Helper(t).Helper()
 	dir := os.Getenv("RESTIC_TEST_REPO")
 	if dir != "" {
 		_, err := os.Stat(dir)

internal/test/helper.go

@@ -0,0 +1,15 @@
+// +build go1.9
+
+package test
+
+import "testing"
+
+// Helperer marks the current function as a test helper.
+type Helperer interface {
+	Helper()
+}
+
+// Helper returns a function that marks the current function as a helper function.
+func Helper(t testing.TB) Helperer {
+	return t
+}

internal/test/helper_go18.go

@@ -0,0 +1,19 @@
+// +build !go1.9
+
+package test
+
+import "testing"
+
+// Helperer marks the current function as a test helper.
+type Helperer interface {
+	Helper()
+}
+
+type fakeHelper struct{}
+
+func (fakeHelper) Helper() {}
+
+// Helper returns a function that marks the current function as a helper function.
+func Helper(t testing.TB) Helperer {
+	return fakeHelper{}
+}