mockor

Generic mocker method generator for mockito or mocktail. One mock method to mock any class just like in the original mockito.

Pub Package.

Getting Started

Add the dependencies

dev_dependencies:
  mockor: ^1.0.0

Add a mocker.dart file in your test folder and a mock method with a @GenerateMocker annotation. Don't forget to import mockito here.


// This import is used by the generated mockor file to add Mockito's `@GenerateMocks` annotation.
// This need to be added manually.
import 'package:mockito/mockor.dart';

// <file_name>.mocks.dart will be generated by Mockito which contain all the generated mocks.
// This needs to be added manually.
import 'example.mocks.dart';

import 'package:mockor/mockor.dart';

part 'example.mockor.dart';

abstract class ExampleUseCase {
  int example(int i);
}

abstract class ExampleUseCase2 {
  void example2();
}

@GenerateMocker([
  ExampleUseCase,
  ExampleUseCase2,
])
T mock<T extends Object>({bool relaxed = false}) => _$mock<T>(relaxed: relaxed);

To use the generated mocks, simply import and call the defined mock function

import '../../mocker.dart';

void main() {
  late ExampleUseCase exampleUseCase;
  late ExampleUseCase2 exampleUseCase2;

  setUp(() {
    // this will return [MockExampleUseCase]
    exampleUseCase = mock();
    exampleUseCase2 = mock();
  });
}

for more info check out the example module.

Getting Started using mocktail

Follow steps like before with slight modifications to mocker.dart file

// This import will be used for generating the mocks.
// This needs to be added manually. 
import 'package:mocktail/mocktail.dart';

import 'package:mockor/mockor.dart';

part 'mocker.mockor.dart';

@GenerateMocker.mocktail(
  [
    ExampleUseCase,
    ExampleUseCase2,
  ],
  // optionally generate relaxedVoid parameter which prevents missing stub errors for `void` and `Future<void>`
  generateRelaxedVoidParameter: true,
  // optionally generate fallback values for non null params to use `any()`
  generateMocktailFallbackValues: GenerateMocktailFallbackValues(
    [ExampleModel],
    // optionally register a mock class for all the non primitive parameters of all the methods in each class of [GenerateMocker.types] automatically.
    autoDetect: true,
  ),
)
T mock<T extends Object>({bool relaxed = false, bool? relaxedVoid}) =>
    _$_mock<T>(relaxed: relaxed, relaxedVoid: relaxedVoid);

//define a global register fallback values method
void registerFallbackValuesAll() {
  _$registerFallbackValues();
}

Create flutter_test_config.dart in the root of your test folder.

import 'dart:async';
import 'package:flutter_test/flutter_test.dart';

import 'mocker.dart';

Future<void> testExecutable(FutureOr<void> Function() testMain) async {
  // this will be executed before the main function of any test file in the test folder.
  setUpAll(() {
    registerFallbackValuesAll();
  });
  await testMain();
}

Optional relaxed param to return null on missing stub

The _$mock<T>() method takes in an optional bool parameter named relaxed.

If it's false, throwOnMissingStub is called on the Mock object with so that you get exceptions when you try to call a method that is not stubbed.

However if it's true, a TypeError is thrown when the method has a non null return type. On nullable return types, null is returned for missing stubs.

It is true by default for mocktail It is false by default for mockito

T mock<T extends Object>({bool relaxed = false}) => _$mock<T>(relaxed: relaxed);

final myService = mock<MyService>(relaxed: true);
when(myService.doSomethingElse()).thenReturn(true);

myService.doSomething(); // this will throw an exception
myService.doSomethingElse(); // this will not throw an exception

For more info check out the example module.

Main Advantage over vanilla Mockito

You can always work with the base type

  • Renaming the class will not break tests.
  • Find usages will not miss anything
  • Never have to import/depend on mocks directly

Optional relaxed parameter at runtime

An optional relaxed parameter is added to the generated _$mock method. When set to true, null is returned for missing nullable stubs. And TypeError for non null missing stubs.

This is further explained above.

Advantage over vanilla Mocktail

Fast Code Generation

Even though Mocktail was created to avoid code generation, here code generation is required but only for the one file with the generic mock function. There's no dependency to generated code in any of your tests. And each mock class is only 1 line long.

Private Mock classes

The generated mock classes are private so cannot be imported. Simply call the global mock method. This makes it easier for all developers to follow consistent code conventions.

Generate registerFallbackValues function

An annoying drawback of mocktail is that you need to register fallback values if you want to call the any() function on them. With Mockor, you can generate a registerFallbackValues function where you can either specify the types manually or let the generator auto detect them. Check getting started above for more info.

Optional relaxed parameter

An optional relaxed parameter is added to the generated _$mock method. When set to true, null is returned for missing nullable stubs. And TypeError for non null missing stubs.

This is further explained above.

Optional relaxedVoid parameter (mocktail only feature)

An optional relaxed parameter is added to the generated _$mock method. When set to true, unstubbed void- and Future<void> methods don't throw errors.

FAQ

How can I hide the generated mock classes from auto import?

in the root of your project add an analysis_options.yaml with following content:

analyzer:
  exclude:
    - '**/*.mocks.dart' # Mockito @GenerateMocks

Troubleshooting

"Error, a mock class for 'MockExampleUseCase' has not been generated yet."

The mocker method only supports returning a mock instance for it's base type.

Error when using any: "The argument type 'Null' can't be assigned to the parameter type..."

To be able to use of any, you need the mocked type and not the base type. An asMock extension function is generated for this purpose.

extension ExampleUseCaseAsMockExtension on ExampleUseCase {
  MockExampleUseCase asMock() => this as MockExampleUseCase;
}

Then in your test:

abstract class ExampleUseCase {
  int example(int i);
}
final ExampleUseCase useCase = mock();
// asMock required becuase int i is non null and `any` returns null. the method is overriden with a nullable param in MockExampleUseCase.
when(useCase.asMock().example(any)).thenReturn(1)

Please read Mockito's Null Safety README for more info.

Libraries

mockor