Flutter 中的单元测试通过 BuildContext

问题描述：

我在 Dart 类中有一个方法，它接受 BuildContext 参数，如下:

I have a method in a Dart class, which accepts BuildContext parameter, as follows:

class MyClass {

  <return_type> myMethodName(BuildContext context, ...) {
        ...
        doSomething
        return something;
    }
}

我想测试该方法是否按预期工作:

I want to test that the method works as expected:

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:mockito/mockito.dart';
...

void main() {
  MyClass sut;

  setUp(() {
    sut = MyClass();
  });

  test('me testing', () {

    var actual = sut.myMethodName(...);        

    expect(actual, something);
  });
}

当然不行，因为方法myMethodName需要一个参数BuildContext类型.该值在整个应用程序本身中都可用，但不确定在我的单元测试中从何处获取该值.

Of course, it won't work, because the method myMethodName needs a parameter BuildContext type. This value is available throughout the application itself, but not sure where to get that from in my unit tests.

答

您实际上可以模拟 BuildContext 以便测试将无头运行.我认为它更好，但可能不是您正在寻找的解决方案.

You can actually mock the BuildContext so the test will run headless. I think it's better but might be not a solution that you are looking for.

BuildContext 是一个抽象类，因此它不能被实例化.任何抽象类都可以通过创建该类的实现来模拟.如果我以您的示例为例，则代码将如下所示:

BuildContext is an abstract class therefore it cannot be instantiated. Any abstract class can be mocked by creating implementations of that class. If I take your example then the code will look like this:

class MockBuildContext extends Mock implements BuildContext {}

void main() {
   MyClass sut;
   MockBuildContext _mockContext;

   setUp(() {
     sut = MyClass();
     _mockContext = MockBuildContext();
   });

   test('me testing', () {

   var actual = sut.myMethodName(_mockContext, ...);        

   expect(actual, something);
  });
}

Flutter 中的单元测试通过 BuildContext

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