ref(tests): adds WaitForLine and CreateVolume test helpers

Author: romansergey

tests/dockercli/dockercli.go

@@ -125,6 +125,14 @@ func NewClient() (
 	return
 }
 
+func CreateVolume(cli *client.DockerCli, name string, path string) {
+  RunContainer(cli,
+           "--name", name,
+           "-v", path,
+           "ubuntu-debootstrap:14.04", "/bin/true")
+}
+
+
 // PrintToStdout prints a string to stdout.
 func PrintToStdout(t *testing.T, stdout *io.PipeReader,
 	stdoutPipe *io.PipeWriter, stoptag string) string {
@@ -146,6 +154,25 @@ func PrintToStdout(t *testing.T, stdout *io.PipeReader,
 	return result
 }
 
+func WaitForLine(t *testing.T, stdout *io.PipeReader, stoptag string, trace bool) string {
+	var result string
+	r := bufio.NewReader(stdout)
+	for {
+		cmdBytes, err := r.ReadString('\n')
+		if err != nil {
+			break
+		}
+		result = cmdBytes
+		if trace {
+			fmt.Print(cmdBytes)
+		}
+		if strings.Contains(cmdBytes, stoptag) == true {
+			break
+		}
+	}
+	return result
+}
+
 // GetInspectData prints and returns `docker inspect` data for a container.
 func GetInspectData(t *testing.T, format string, container string) string {
 	var inspectData string