diff --git a/libcontainer/logs/logs_linux_test.go b/libcontainer/logs/logs_linux_test.go
index 17bcf6e05..d6563fd2e 100644
--- a/libcontainer/logs/logs_linux_test.go
+++ b/libcontainer/logs/logs_linux_test.go
@@ -11,44 +11,51 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+const msgErr = `"level":"error"`
+
 func TestLoggingToFile(t *testing.T) {
 	l := runLogForwarding(t)
 
-	logToLogWriter(t, l, `{"level": "info","msg":"kitten"}`)
+	msg := `"level":"info","msg":"kitten"`
+	logToLogWriter(t, l, msg)
 	finish(t, l)
-	check(t, l, "kitten")
+	check(t, l, msg, msgErr)
 }
 
 func TestLogForwardingDoesNotStopOnJsonDecodeErr(t *testing.T) {
 	l := runLogForwarding(t)
 
-	logToLogWriter(t, l, "invalid-json-with-kitten")
-	checkWait(t, l, "failed to decode")
+	logToLogWriter(t, l, `"invalid-json-with-kitten"`)
+	checkWait(t, l, msgErr, "")
 
 	truncateLogFile(t, l.file)
 
-	logToLogWriter(t, l, `{"level": "info","msg":"puppy"}`)
+	msg := `"level":"info","msg":"puppy"`
+	logToLogWriter(t, l, msg)
 	finish(t, l)
-	check(t, l, "puppy")
+	check(t, l, msg, msgErr)
 }
 
 func TestLogForwardingDoesNotStopOnLogLevelParsingErr(t *testing.T) {
 	l := runLogForwarding(t)
 
-	logToLogWriter(t, l, `{"level": "alert","msg":"puppy"}`)
-	checkWait(t, l, "failed to parse log level")
+	msg := `"level":"alert","msg":"puppy"`
+	logToLogWriter(t, l, msg)
+	checkWait(t, l, msgErr, msg)
 
 	truncateLogFile(t, l.file)
 
-	logToLogWriter(t, l, `{"level": "info","msg":"puppy"}`)
+	msg = `"level":"info","msg":"puppy"`
+	logToLogWriter(t, l, msg)
 	finish(t, l)
-	check(t, l, "puppy")
+	check(t, l, msg, msgErr)
 }
 
 func TestLogForwardingStopsAfterClosingTheWriter(t *testing.T) {
 	l := runLogForwarding(t)
 
-	logToLogWriter(t, l, `{"level": "info","msg":"sync"}`)
+	msg := `"level":"info","msg":"sync"`
+	logToLogWriter(t, l, msg)
 
 	// Do not use finish() here as we check done pipe ourselves.
 	l.w.Close()
@@ -58,12 +65,12 @@ func TestLogForwardingStopsAfterClosingTheWriter(t *testing.T) {
 		t.Fatal("log forwarding did not stop after closing the pipe")
 	}
 
-	check(t, l, "sync")
+	check(t, l, msg, msgErr)
 }
 
 func logToLogWriter(t *testing.T, l *log, message string) {
 	t.Helper()
-	_, err := l.w.Write([]byte(message + "\n"))
+	_, err := l.w.Write([]byte("{" + message + "}\n"))
 	if err != nil {
 		t.Fatalf("failed to write %q to log writer: %v", message, err)
 	}
@@ -119,21 +126,24 @@ func truncateLogFile(t *testing.T, file *os.File) {
 	}
 }
 
-// check checks that file contains txt
-func check(t *testing.T, l *log, txt string) {
+// check checks that the file contains txt and does not contain notxt.
+func check(t *testing.T, l *log, txt, notxt string) {
 	t.Helper()
 	contents, err := ioutil.ReadFile(l.file.Name())
 	if err != nil {
 		t.Fatal(err)
 	}
-	if !bytes.Contains(contents, []byte(txt)) {
-		t.Fatalf("%q does not contain %q", string(contents), txt)
+	if txt != "" && !bytes.Contains(contents, []byte(txt)) {
+		t.Fatalf("%s does not contain %s", contents, txt)
+	}
+	if notxt != "" && bytes.Contains(contents, []byte(notxt)) {
+		t.Fatalf("%s does contain %s", contents, notxt)
 	}
 }
 
-// checkWait checks that file contains txt. If the file is empty,
+// checkWait is like check, but if the file is empty,
 // it waits until it's not.
-func checkWait(t *testing.T, l *log, txt string) {
+func checkWait(t *testing.T, l *log, txt string, notxt string) {
 	t.Helper()
 	const (
 		delay = 100 * time.Millisecond
@@ -153,5 +163,5 @@ func checkWait(t *testing.T, l *log, txt string) {
 		time.Sleep(delay)
 	}
 
-	check(t, l, txt)
+	check(t, l, txt, notxt)
 }