[audio] Refactor audio driver to simplify interface

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

examples/audio.go

@@ -11,11 +11,11 @@ func main() {
 	gbot := gobot.NewGobot()
 
 	e := audio.NewAudioAdaptor("sound")
-	laser := audio.NewAudioDriver(e, "laser", nil)
+	laser := audio.NewAudioDriver(e, "laser", "./examples/laser.mp3")
 
 	work := func() {
-		gobot.Every(1*time.Second, func() {
-			laser.Sound("./examples/laser.mp3")
+		gobot.Every(2 * time.Second, func() {
+			laser.Play()
 		})
 	}
 

gobottest/gobottest.go

@@ -6,6 +6,8 @@ import (
 	"runtime"
 	"strings"
 	"testing"
+	"os"
+	"os/exec"
 )
 
 var errFunc = func(t *testing.T, message string) {
@@ -33,3 +35,11 @@ func Refute(t *testing.T, a interface{}, b interface{}) {
 			a, reflect.TypeOf(a), b, reflect.TypeOf(b)))
 	}
 }
+
+func ExecCommand(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
+}

platforms/audio/audio_adaptor_test.go

@@ -2,7 +2,6 @@
 package audio
 
 import (
-	"os"
 	"os/exec"
 	"testing"
 
@@ -49,16 +48,8 @@ func TestAudioAdaptorSoundWithNonexistingFilename(t *testing.T) {
 	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
+	execCommand = gobottest.ExecCommand
 
 	a := NewAudioAdaptor("tester")
 	defer func() { execCommand = exec.Command }()

platforms/audio/audio_driver.go

@@ -3,7 +3,6 @@
 package audio
 
 import (
-	"fmt"
 	"github.com/hybridgroup/gobot"
 	"time"
 )
@@ -17,15 +16,15 @@ type AudioDriver struct {
 	halt       chan bool
 	gobot.Eventer
 	gobot.Commander
-	queue chan string
+	filename string
 }
 
-func NewAudioDriver(a *AudioAdaptor, name string, queue chan string) *AudioDriver {
+func NewAudioDriver(a *AudioAdaptor, name string, filename string) *AudioDriver {
 	d := &AudioDriver{
 		name:       name,
 		connection: a,
 		interval:   500 * time.Millisecond,
-		queue:      queue,
+		filename:   filename,
 		halt:       make(chan bool, 0),
 		Eventer:    gobot.NewEventer(),
 		Commander:  gobot.NewCommander(),
@@ -35,6 +34,8 @@ func NewAudioDriver(a *AudioAdaptor, name string, queue chan string) *AudioDrive
 
 func (d *AudioDriver) Name() string { return d.name }
 
+func (d *AudioDriver) Filename() string { return d.filename }
+
 func (d *AudioDriver) Connection() gobot.Connection {
 	return d.connection
 }
@@ -43,31 +44,18 @@ func (d *AudioDriver) Sound(fileName string) []error {
 	return d.Connection().(*AudioAdaptor).Sound(fileName)
 }
 
+func (d *AudioDriver) Play() []error {
+	return d.Sound(d.Filename())
+}
+
 func (d *AudioDriver) adaptor() *AudioAdaptor {
 	return d.Connection().(*AudioAdaptor)
 }
 
 func (d *AudioDriver) Start() (err []error) {
-	go d.serve(d.queue)
 	return
 }
 
 func (d *AudioDriver) Halt() (err []error) {
 	return
 }
-
-// Use semaphore to control how many sounds might be playing at a time
-var sem = make(chan int, 1)
-
-// See example at https://golang.org/doc/effective_go.html#concurrency
-// Purpose: receive messages on channel, but throttle execution of playing
-func (d *AudioDriver) serve(queue chan string) {
-	for req := range queue {
-		sem <- 1
-		go func(req string) {
-			fmt.Printf("Playing sound %v\n", req)
-			d.Sound(req)
-			<-sem
-		}(req)
-	}
-}

platforms/audio/audio_driver_test.go

@@ -4,14 +4,17 @@ package audio
 
 import (
 	"testing"
+	"os/exec"
 
 	"github.com/hybridgroup/gobot/gobottest"
 )
 
 func TestAudioDriver(t *testing.T) {
-	d := NewAudioDriver(NewAudioAdaptor("conn"), "dev", nil)
+	d := NewAudioDriver(NewAudioAdaptor("conn"), "dev", "../../examples/laser.mp3")
 
 	gobottest.Assert(t, d.Name(), "dev")
+	gobottest.Assert(t, d.Filename(), "../../examples/laser.mp3")
+
 	gobottest.Assert(t, d.Connection().Name(), "conn")
 
 	gobottest.Assert(t, len(d.Start()), 0)
@@ -20,8 +23,18 @@ func TestAudioDriver(t *testing.T) {
 }
 
 func TestAudioDriverSoundWithNoFilename(t *testing.T) {
-	d := NewAudioDriver(NewAudioAdaptor("conn"), "dev", nil)
+	d := NewAudioDriver(NewAudioAdaptor("conn"), "dev", "")
 
 	errors := d.Sound("")
 	gobottest.Assert(t, errors[0].Error(), "Requires filename for audio file.")
 }
+
+func TestAudioDriverSoundWithDefaultFilename(t *testing.T) {
+	execCommand = gobottest.ExecCommand
+	defer func() { execCommand = exec.Command }()
+
+	d := NewAudioDriver(NewAudioAdaptor("conn"), "dev", "../../examples/laser.mp3")
+
+	errors := d.Play()
+	gobottest.Assert(t, len(errors), 0)
+}