如何在 symfony 中模拟表格 PhpUnit 的值

Question

嗨，我尝试在 controller 中模拟具有编辑操作值的表单

    Test Mock
    $form = $this->getMockBuilder(FormInterface::class)->disableOriginalConstructor()
        ->getMock();
    if ($submittedForm) {

        $form->method('getData')->willReturn('example.png');

        $form->method('isSubmitted')->willReturn(true);
        $form->method('isValid')->willReturn(true);


    }
    $formData = array(
        'deceasedImage' => 'example.jpg',
        'image' => 'example.png',
    );
    $form->submit($formData);
    $form['deceased_image']='example.png';

    $formInterface = $this->createMock(FormBuilderInterface::class);
    $formInterface->method('create')
        ->willReturn($form);
    return $formInterface;

controller $uploadedFileDeceased = $form['deeased_image']->getData() 中的行错误； 来自终端的错误错误：调用 null 上的成员 function getData()，如何执行此操作？