CODEWITHSUNDEEP
testingflutterdart
zeucxb
zeucxb

Reputation: 1104

How can I test a void static method in Dart/Flutter?

I'm trying to unit test a class that has static void methods.

I'm using Mockito (verify) to check if a void method call another function as expected, but it doesn't work to static methods.

class SystemUtils {
  // ...

  static void handleError(bool isDebug, FlutterErrorDetails details) {
    if (isDebug) {
      FlutterError.dumpErrorToConsole(details);
    } else {
      Crashlytics.instance.onError(details);
    }
  }
}

Upvotes: 2

Views: 5578

Answers (2)

VarunS2002
VarunS2002

Reputation: 391

What I think you're looking for (example):

Code to be tested:

class TestExpect {
  static void noParameter() {
    bool inDebugMode = false;
    assert(inDebugMode = false);
  }

  static void hasParameter(bool toBeIgnored) {
    bool inDebugMode = false;
    assert(inDebugMode = false);
  }
}

Unit Testing Code:

void main() {
  test('static void method', () {
    expect(TestExpect.noParameter, throwsA(isA<AssertionError>()));
  });

  test('static void method parameter', () {
    expect(() => TestExpect.hasParameter(true), throwsA(isA<AssertionError>()));
  });
}

Upvotes: 1

zeucxb
zeucxb

Reputation: 1104

I solved changing the class.

The method isn't static anymore and now I receive the external methods in the constructor as default values.

import 'package:firebase_crashlytics/firebase_crashlytics.dart';
import 'package:flutter/cupertino.dart';

class SystemUtils {
  SystemUtils({
    debugErrorHandler,
    releaseErrorHandler,
  })  : _debugErrorHandler =
            debugErrorHandler ?? FlutterError.dumpErrorToConsole,
        _releaseErrorHandler =
            releaseErrorHandler ?? Crashlytics.instance.onError;

  final void Function(FlutterErrorDetails) _debugErrorHandler;
  final void Function(FlutterErrorDetails) _releaseErrorHandler;

  static bool isInDebugMode() {
    bool inDebugMode = false;
    assert(inDebugMode = true);

    return inDebugMode;
  }

  void handleError(bool isDebug, FlutterErrorDetails details) {
    if (isDebug) {
      _debugErrorHandler(details);
    } else {
      _releaseErrorHandler(details);
    }
  }
}

Now I can replace the method on constructor when I wanted (in tests for example).

group('handleError', () {
    test('should call _debugErrorHandler if isDebug is true', () {
      const isDebug = true;
      const details = FlutterErrorDetails(exception: 'error exception');

      void debugErrorHandler(FlutterErrorDetails localDetails) {
        expect(localDetails, details);
      }

      final SystemUtils systemUtils = SystemUtils(debugErrorHandler: debugErrorHandler);

      systemUtils.handleError(isDebug, details);
    });
});

But I still want to know if it's possible to test void static methods in Dart.

Upvotes: 0

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