Adding instance check in JobMarshaler

src/Queue/Marshal/JobMarshaler.php

@@ -30,6 +30,9 @@ public function unmarshal($source)
      */
     public function marshal(JobInterface $job)
     {
+        if (!($job instanceof Job)) {
+            throw new MarshalException(get_class($job) . ' is not a ' . Job::class);
+        }
         return json_encode($job->getBody());
     }
 }

tests/Queue/Marshaler/JobMarshalerTest.php

@@ -2,43 +2,59 @@
 namespace Disque\Test\Queue\Marshaler;
 
 use Disque\Queue\Job;
+use Disque\Queue\JobInterface;
 use Disque\Queue\Marshal\JobMarshaler;
 use Disque\Queue\Marshal\MarshalerInterface;
 use Disque\Queue\Marshal\MarshalException;
+use Mockery as m;
 use PHPUnit_Framework_TestCase;
 
 class JobMarshalerTest extends PHPUnit_Framework_TestCase
 {
+    public function tearDown()
+    {
+        parent::tearDown();
+        m::close();
+    }
+
     public function testInstance()
     {
         $m = new JobMarshaler();
         $this->assertInstanceOf(MarshalerInterface::class, $m);
     }
 
-    public function testBodyEmpty()
+    public function testMarshalInvalid()
+    {
+        $job = m::mock(JobInterface::class);
+        $this->setExpectedException(MarshalException::class, get_class($job) . ' is not a ' . Job::class);
+        $m = new JobMarshaler();
+        $m->marshal($job);
+    }
+
+    public function testMarshalEmpty()
     {
         $m = new JobMarshaler();
         $j = new Job();
         $result = $m->marshal($j);
         $this->assertSame('[]', $result);
     }
 
-    public function testBodyNotEmpty()
+    public function testMarshalNotEmpty()
     {
         $m = new JobMarshaler();
         $j = new Job(['test' => 'stuff']);
         $result = $m->marshal($j);
         $this->assertSame('{"test":"stuff"}', $result);
     }
 
-    public function testLoadInvalid()
+    public function testUnmarshalInvalid()
     {
         $this->setExpectedException(MarshalException::class, 'Could not deserialize {"wrong"!');
         $m = new JobMarshaler();
         $m->unmarshal('{"wrong"!');
     }
 
-    public function testLoadEmpty()
+    public function testUnmarshalEmpty()
     {
         $m = new JobMarshaler();
         $j = $m->unmarshal('{"test":"stuff"}');