diff --git a/samples/client/petstore/php/SwaggerClient-php/tests/PetApiTest.php b/samples/client/petstore/php/SwaggerClient-php/tests/PetApiTest.php
index c29b6d2686f..500b03896a0 100644
--- a/samples/client/petstore/php/SwaggerClient-php/tests/PetApiTest.php
+++ b/samples/client/petstore/php/SwaggerClient-php/tests/PetApiTest.php
@@ -373,6 +373,17 @@ public function testDefaultValues()
         $this->assertSame('red', $animal->getColor());
     }
 
+    /**
+     * test invalid argument
+     *
+     * @expectedException \InvalidArgumentException
+     */
+    public function testInvalidArgument()
+    {
+        // the argument is required, and we must specify one or some from 'available', 'pending', 'sold'
+        $this->api->findPetsByStatus([]);
+    }
+
 //    Disabled as currently we don't have any endpoint that would return file
 //    For testing I just replaced url and return type in Api method.
 //    public function testDownloadingLargeFile()
diff --git a/samples/client/petstore/php/SwaggerClient-php/tests/StoreApiTest.php b/samples/client/petstore/php/SwaggerClient-php/tests/StoreApiTest.php
index f413737461c..4be179c2bc7 100644
--- a/samples/client/petstore/php/SwaggerClient-php/tests/StoreApiTest.php
+++ b/samples/client/petstore/php/SwaggerClient-php/tests/StoreApiTest.php
@@ -18,43 +18,7 @@ public function testGetInventory()
     {
         $result = $this->api->getInventory();
 
-        $this->assertInternalType("array", $result);
-        $this->assertInternalType("int", $result['available']);
+        $this->assertInternalType('array', $result);
+        $this->assertInternalType('int', $result['available']);
     }
-
-    /*
-     * comment out as we've removed invalid endpoints from the spec, we'll introduce something
-     * similar in the future when we've time to update the petstore server
-     *
-    // test get inventory
-    public function testGetInventoryInObject()
-    {
-        $result = $this->api->getInventoryInObject();
-
-        $this->assertInternalType("array", $result);
-        $this->assertInternalType("int", $result['available']);
-    }
-     */
-
-    /**
-     * test empty array response
-     *
-     * Make sure empty arrays from a producer is actually returned as
-     * an empty array and not some other value. At some point it was
-     * returned as null because the code stumbled on PHP loose type
-     * checking (not on empty array is true, same thing could happen
-     * with careless use of empty()).
-     */
-//    public function testEmptyArrayResponse()
-//    {
-//        // this call returns and empty array
-//        $response = $this->api->findPetsByStatus(array());
-//
-//        // make sure this is an array as we want it to be
-//        $this->assertInternalType("array", $response);
-//
-//        // make sure the array is empty just in case the petstore
-//        // server changes its output
-//        $this->assertEmpty($response);
-//    }
 }