[Console] explicit assertion for ArgvInput::getFirstArgument() with no arguments

Author: nanocom

src/Symfony/Component/Console/Tests/Input/ArgvInputTest.php

@@ -257,7 +257,7 @@ public function testParseEmptyStringArgument()
     public function testGetFirstArgument()
     {
         $input = new ArgvInput(array('cli.php', '-fbbar'));
-        $this->assertEquals('', $input->getFirstArgument(), '->getFirstArgument() returns the first argument from the raw input');
+        $this->assertNull($input->getFirstArgument(), '->getFirstArgument() returns null when there is no arguments');
 
         $input = new ArgvInput(array('cli.php', '-fbbar', 'foo'));
         $this->assertEquals('foo', $input->getFirstArgument(), '->getFirstArgument() returns the first argument from the raw input');