Flutter 与提供商进行单元测试

Question

I am not able to use the provider in unit testing I am using the following code. I am getting this error

00:02 +2 -1: test student controller with add and remove student test controller for add new set [E]                                            
  Null check operator used on a null value
  package:provider/src/provider.dart 274:20  Provider.of
  test/student_controller_test.dart 53:22    main.<fn>.<fn>
  test/student_controller_test.dart 36:53    main.<fn>.<fn>

class MockBuildContext extends Mock implements BuildContext {}

void main() {
  late MockBuildContext _mockContext;

  setUpAll(() {
    _mockContext = MockBuildContext();
  });


test('test student controller for add new student', () async {
      List<Students> sts = [
        Students(
            name: 'Barbels',
            age: 21,
            weight: 70,
          ),
         Students(
            name: 'Hazel',
            age: 31,
            weight: 60,
          ),
      ];
      var id = '1';
      print(_mockContext);
      MyController.saveStuden(_mockContext, id, sets);
      print(Provider.of<StudentProvider>(_mockContext, listen: false)
          .items
          .length);
});

Answer 1

You need to register the controller to be run before tests.

void main() {

  late MockBuildContext _mockContext;
  late MyController _controller;

  setUpAll(() {
    _controller = MyController();
    _mockContext = MockBuildContext();
  });


test('test student controller for add new student', () async {
      List<Students> sts = [
        Students(
            name: 'Barbels',
            age: 21,
            weight: 70,
          ),
         Students(
            name: 'Hazel',
            age: 31,
            weight: 60,
          ),
      ];
      var id = '1';
      print(_mockContext);

      _controller.saveStuden(_mockContext, id, sets);

      print(Provider.of<StudentProvider>(_mockContext, listen: false)
          .items
          .length);
});