Fix client push panic (#134)

* Fix(panic) fix client push panic
* feat(test) check bad device token

Author: pshopper

client.go

@@ -154,7 +154,10 @@ func (c *Client) PushWithContext(ctx Context, n *Notification) (*Response, error
 	}
 
 	url := fmt.Sprintf("%v/3/device/%v", c.Host, n.DeviceToken)
-	req, _ := http.NewRequest("POST", url, bytes.NewBuffer(payload))
+	req, err := http.NewRequest("POST", url, bytes.NewBuffer(payload))
+	if err != nil {
+		return nil, err
+	}
 
 	if c.Token != nil {
 		c.setTokenHeader(req)

client_test.go

@@ -102,6 +102,15 @@ func TestClientBadTransportError(t *testing.T) {
 	assert.Nil(t, res)
 }
 
+func TestClientBadDeviceToken(t *testing.T) {
+	n := &apns.Notification{}
+	n.DeviceToken = "DGw\aOoD+HwSroh#Ug]%xzd]"
+	n.Payload = []byte(`{"aps":{"alert":"Hello!"}}`)
+	res, err := mockClient("https://api.push.apple.com").Push(n)
+	assert.Error(t, err)
+	assert.Nil(t, res)
+}
+
 func TestClientNameToCertificate(t *testing.T) {
 	crt, _ := certificate.FromP12File("certificate/_fixtures/certificate-valid.p12", "")
 	client := apns.NewClient(crt)