Getting type 'Null' is not a subtype of type 'Future<Response>' in Flutter - flutter

Question

I'm trying to run a text in flutter using mockito but I have been getting a error of
type 'Null' is not a subtype of type 'Future<Response>'
Below is the code
class MockClient extends Mock implements http.Client {}
void main() {
var client = MockClient();
var sut = AuthApi('http:baseUrl', client);
setUp(() {
client;
sut;
});
group('signin', () {
var credential = Credential(
type: AuthType.email,
email: 'email#email',
password: 'pass',
);
test('should return error when status is not 200', () async {
when(client.post(Uri(), body: anyNamed('body')))
.thenAnswer((_) async => http.Response('{}', 404));
var result = await sut.signIn(credential);
expect(result, isA<ErrorResult>());
});
});
}
I have tried to pass
when(client.post(any, body: anyNamed('body')))
but I got any error of: The argument type 'Null' can't be assigned to the parameter type 'Uri'

Answer 1

Since Mockito migrated to a null safety code, you need to Override the method with a new declaration inside the mock class. At a body of the override method call super.noSuchMethod, passing in an Invocation object which includes all of the values passed to the override, and pass a second argument to super.noSuchMethod, a value which can function as a return value.
Here is an example:
class MockClient extends Mock implements http.Client {
#override
Future<http.Response> post(Uri uri, {String body}) => super.noSuchMethod(Invocation.method(#post, [uri, body]), returnValue: http.Response('{}', 404));
}
Please note that your method parameters may be different