fix the test expectations

src/FFMpeg/Media/Frame.php

@@ -115,8 +115,7 @@ class Frame extends AbstractMediaType
             $commands = array_merge($commands, $filter->apply($this));
         }
 
-        // without output filename when return binary string
-        if(!$returnBase64) {
+        if (!$returnBase64) {
             $commands = array_merge($commands, array($pathfile));
         }
 

tests/Unit/Media/FrameTest.php

@@ -61,7 +61,9 @@ class FrameTest extends AbstractMediaTestCase
 
         $pathfile = '/target/destination';
 
-        array_push($commands, $pathfile);
+        if (!$base64) {
+            array_push($commands, $pathfile);
+        }
 
         $driver->expects($this->once())
             ->method('command')