Nelmio\Alice\Definition\ServiceReference\MutableReference::setId PHP Method

    public function setId(string $id)
    {
        $this->id = $id;
    }

 public function testIsMutable()
 {
     $caller = new MutableReference();
     $method = 'setUsername';
     $arguments = [$arg0 = new \stdClass()];
     $definition = new MethodCallWithReference($caller, $method, $arguments);
     // Mutate injected elements
     $caller->setId('user.factory');
     $arg0->foo = 'bar';
     // Mutate retrieved elements
     /** @var MutableReference $caller */
     $caller = $definition->getCaller();
     $caller->setId('user.factory');
     $arguments = $definition->getArguments();
     $arguments[0]->foz = 'baz';
     $this->assertEquals(new MutableReference(), $definition->getCaller());
     $this->assertEquals([StdClassFactory::create(['foo' => 'bar', 'foz' => 'baz'])], $definition->getArguments());
 }