[audio] Test coverage for exexcution of audio adaptor

Signed-off-by: deadprogram <ron@hybridgroup.com>

platforms/audio/audio_adaptor.go

@@ -53,8 +53,7 @@ func (a *AudioAdaptor) Sound(fileName string) []error {
 		return errorsList
 	}
 
-	cmd := exec.Command(commandName, fileName)
-	err = cmd.Start()
+	err = RunCommand(commandName, fileName)
 	if err != nil {
 		log.Println(err)
 		errorsList = append(errorsList, err)
@@ -75,3 +74,11 @@ func CommandName(fileName string) (commandName string, err error) {
 		return "", errors.New("Unknown filetype for audio file.")
 	}
 }
+
+var execCommand = exec.Command
+
+func RunCommand(audioCommand string, filename string) error {
+	cmd := execCommand(audioCommand, filename)
+	err := cmd.Start()
+	return err
+}

platforms/audio/audio_adaptor_test.go

@@ -2,6 +2,8 @@
 package audio
 
 import (
+	"os"
+	"os/exec"
 	"testing"
 
 	"github.com/hybridgroup/gobot/gobottest"
@@ -46,3 +48,22 @@ func TestAudioAdaptorSoundWithNonexistingFilename(t *testing.T) {
 	errors := a.Sound("doesnotexist.mp3")
 	gobottest.Assert(t, errors[0].Error(), "stat doesnotexist.mp3: no such file or directory")
 }
+
+func fakeExecCommand(command string, args ...string) *exec.Cmd {
+	cs := []string{"-test.run=TestHelperProcess", "--", command}
+	cs = append(cs, args...)
+	cmd := exec.Command(os.Args[0], cs...)
+	cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
+	return cmd
+}
+
+func TestAudioAdaptorSoundWithValidMP3Filename(t *testing.T) {
+	execCommand = fakeExecCommand
+
+	a := NewAudioAdaptor("tester")
+	defer func() { execCommand = exec.Command }()
+
+	errors := a.Sound("../../examples/laser.mp3")
+
+	gobottest.Assert(t, len(errors), 0)
+}