Fix null reference on failure to connect

Refactor sphero adaptor

platforms/sphero/sphero_adaptor.go

@@ -15,7 +15,7 @@ type SpheroAdaptor struct {
 	port      string
 	sp        io.ReadWriteCloser
 	connected bool
-	connect   func(*SpheroAdaptor) (err error)
+	connect   func(string) (io.ReadWriteCloser, error)
 }
 
 // NewSpheroAdaptor returns a new SpheroAdaptor given a name and port
@@ -23,14 +23,8 @@ func NewSpheroAdaptor(name string, port string) *SpheroAdaptor {
 	return &SpheroAdaptor{
 		name: name,
 		port: port,
-		connect: func(a *SpheroAdaptor) (err error) {
-			c := &serial.Config{Name: a.Port(), Baud: 115200}
-			s, err := serial.OpenPort(c)
-			if err != nil {
-				return err
-			}
-			a.sp = s
-			return
+		connect: func(port string) (io.ReadWriteCloser, error) {
+			return serial.OpenPort(&serial.Config{Name: port, Baud: 115200})
 		},
 	}
 }
@@ -39,10 +33,12 @@ func (a *SpheroAdaptor) Port() string { return a.port }
 
 // Connect initiates a connection to the Sphero. Returns true on successful connection.
 func (a *SpheroAdaptor) Connect() (errs []error) {
-	if err := a.connect(a); err != nil {
+	if sp, err := a.connect(a.Port()); err != nil {
 		return []error{err}
+	} else {
+		a.sp = sp
+		a.connected = true
 	}
-	a.connected = true
 	return
 }
 
@@ -50,7 +46,7 @@ func (a *SpheroAdaptor) Connect() (errs []error) {
 // it will first close that connection and then establish a new connection.
 // Returns true on Successful reconnection
 func (a *SpheroAdaptor) Reconnect() (errs []error) {
-	if a.connected == true {
+	if a.connected {
 		a.Disconnect()
 	}
 	return a.Connect()
@@ -58,10 +54,12 @@ func (a *SpheroAdaptor) Reconnect() (errs []error) {
 
 // Disconnect terminates the connection to the Sphero. Returns true on successful disconnect.
 func (a *SpheroAdaptor) Disconnect() (errs []error) {
-	if err := a.sp.Close(); err != nil {
-		return []error{err}
+	if a.connected {
+		if err := a.sp.Close(); err != nil {
+			return []error{err}
+		}
+		a.connected = false
 	}
-	a.connected = false
 	return
 }
 

platforms/sphero/sphero_adaptor_test.go

@@ -2,6 +2,7 @@ package sphero
 
 import (
 	"errors"
+	"io"
 	"testing"
 
 	"github.com/hybridgroup/gobot"
@@ -35,8 +36,9 @@ func (nullReadWriteCloser) Close() error {
 
 func initTestSpheroAdaptor() *SpheroAdaptor {
 	a := NewSpheroAdaptor("bot", "/dev/null")
-	a.sp = nullReadWriteCloser{}
-	a.connect = func(a *SpheroAdaptor) (err error) { return nil }
+	a.connect = func(string) (io.ReadWriteCloser, error) {
+		return &nullReadWriteCloser{}, nil
+	}
 	return a
 }
 
@@ -60,12 +62,14 @@ func TestSpheroAdaptorReconnect(t *testing.T) {
 
 func TestSpheroAdaptorFinalize(t *testing.T) {
 	a := initTestSpheroAdaptor()
+	a.Connect()
 	gobot.Assert(t, len(a.Finalize()), 0)
 
 	testAdaptorClose = func() error {
 		return errors.New("close error")
 	}
 
+	a.connected = true
 	gobot.Assert(t, a.Finalize()[0], errors.New("close error"))
 }
 
@@ -73,8 +77,8 @@ func TestSpheroAdaptorConnect(t *testing.T) {
 	a := initTestSpheroAdaptor()
 	gobot.Assert(t, len(a.Connect()), 0)
 
-	a.connect = func(a *SpheroAdaptor) (err error) {
-		return errors.New("connect error")
+	a.connect = func(string) (io.ReadWriteCloser, error) {
+		return nil, errors.New("connect error")
 	}
 
 	gobot.Assert(t, a.Connect()[0], errors.New("connect error"))

platforms/sphero/sphero_driver.go

@@ -180,10 +180,12 @@ func (s *SpheroDriver) Start() (errs []error) {
 // Halt halts the SpheroDriver and sends a SpheroDriver.Stop command to the Sphero.
 // Returns true on successful halt.
 func (s *SpheroDriver) Halt() (errs []error) {
-	gobot.Every(10*time.Millisecond, func() {
-		s.Stop()
-	})
-	time.Sleep(1 * time.Second)
+	if s.adaptor().connected {
+		gobot.Every(10*time.Millisecond, func() {
+			s.Stop()
+		})
+		time.Sleep(1 * time.Second)
+	}
 	return
 }
 

platforms/sphero/sphero_driver_test.go

@@ -58,6 +58,7 @@ func TestSpheroDriverStart(t *testing.T) {
 
 func TestSpheroDriverHalt(t *testing.T) {
 	d := initTestSpheroDriver()
+	d.adaptor().connected = true
 	gobot.Assert(t, len(d.Halt()), 0)
 }