merge branch 'pr-2925'

Akihiro Suda (4):
  Revert "Makefile: rm go 1.13 workaround"
  libcontainer: avoid using t.Cleanup
  go.mod: demote to Go 1.13
  CI: enable Go 1.13 again

LGTMs: kolyskhin cyphar
Closes #2925

libcontainer/logs/logs_linux_test.go

@@ -13,6 +13,7 @@ import (
 
 func TestLoggingToFile(t *testing.T) {
 	l := runLogForwarding(t)
+	defer l.cleanup()
 
 	logToLogWriter(t, l, `{"level": "info","msg":"kitten"}`)
 	finish(t, l)
@@ -21,6 +22,7 @@ func TestLoggingToFile(t *testing.T) {
 
 func TestLogForwardingDoesNotStopOnJsonDecodeErr(t *testing.T) {
 	l := runLogForwarding(t)
+	defer l.cleanup()
 
 	logToLogWriter(t, l, "invalid-json-with-kitten")
 	checkWait(t, l, "failed to decode")
@@ -34,6 +36,7 @@ func TestLogForwardingDoesNotStopOnJsonDecodeErr(t *testing.T) {
 
 func TestLogForwardingDoesNotStopOnLogLevelParsingErr(t *testing.T) {
 	l := runLogForwarding(t)
+	defer l.cleanup()
 
 	logToLogWriter(t, l, `{"level": "alert","msg":"puppy"}`)
 	checkWait(t, l, "failed to parse log level")
@@ -47,6 +50,7 @@ func TestLogForwardingDoesNotStopOnLogLevelParsingErr(t *testing.T) {
 
 func TestLogForwardingStopsAfterClosingTheWriter(t *testing.T) {
 	l := runLogForwarding(t)
+	defer l.cleanup()
 
 	logToLogWriter(t, l, `{"level": "info","msg":"sync"}`)
 
@@ -73,6 +77,9 @@ type log struct {
 	w    io.WriteCloser
 	file string
 	done chan error
+
+	// TODO: use t.Cleanup after dropping support for Go 1.13
+	cleanup func()
 }
 
 func runLogForwarding(t *testing.T) *log {
@@ -81,10 +88,6 @@ func runLogForwarding(t *testing.T) *log {
 	if err != nil {
 		t.Fatal(err)
 	}
-	t.Cleanup(func() {
-		logR.Close()
-		logW.Close()
-	})
 
 	tempFile, err := ioutil.TempFile("", "")
 	if err != nil {
@@ -92,7 +95,6 @@ func runLogForwarding(t *testing.T) *log {
 	}
 	tempFile.Close()
 	logFile := tempFile.Name()
-	t.Cleanup(func() { os.Remove(logFile) })
 
 	logConfig := Config{LogLevel: logrus.InfoLevel, LogFormat: "json", LogFilePath: logFile}
 	loggingConfigured = false
@@ -102,7 +104,13 @@ func runLogForwarding(t *testing.T) *log {
 
 	doneForwarding := ForwardLogs(logR)
 
-	return &log{w: logW, done: doneForwarding, file: logFile}
+	cleanup := func() {
+		os.Remove(logFile)
+		logR.Close()
+		logW.Close()
+	}
+
+	return &log{w: logW, done: doneForwarding, file: logFile, cleanup: cleanup}
 }
 
 func finish(t *testing.T, l *log) {