I am trying to test a class which instatiates another class within it. It is the instatinated class call I want to mock.
Is this possible or is they a way around it/ simpler way I am missing?
Below I have written up a simpler example which still has the same problemts as my main code.
public interface my_interface
{
int returns_25();
}
public class class_i_want_to_mock : my_interface
{
public int returns_25()
{
// TEST SHOULD FAIL SO NEED MOCK TO PASS THE CASE
return 7645745;
}
}
In another namespace (it has access):
public class class_to_test
{
public static int returns_25()
{
class_i_want_to_mock _tempClass= new class_i_want_to_mock ();
// Will return 7645745 unless moq changes return value
int _temp_int = _tempClass.returns_25()
return _temp_int;
}
}
My test (which fails):
[Test]
public void test_returns_25()
{
// Mock
Mock<my_interface> myMock = new Mock<my_interface>();
myMock.Setup(m => m.returns_25()).Returns(25);
// Act
int return_number = class_to_test.returns_25();
// Assert
Assert.AreEqual(25, return_number);
}
Here is working code thanks to the injection idea from JSteward above.
Code is in same order
public interface my_interface
{
int returns_25();
}
public class class_i_want_to_mock : my_interface
{
public int returns_25()
{
// TEST SHOULD FAIL SO NEED MOCK TO PASS THE CASE
return 7645745;
}
}
Next class, notice the injection of the interface
public class class_to_test
{
public static int returns_25(my_interface _temp_interface)
{
// Will return 7645745 unless moq changes return value
int _temp_int = _temp_interface.returns_25()
return _temp_int;
}
}
And the test. Note the object of the Mock class has to be used (myMock.Object)
[Test]
public void test_returns_25()
{
// Mock
Mock<my_interface> myMock = new Mock<my_interface>();
myMock.Setup(m => m.returns_25()).Returns(25);
// Act
int return_number = class_to_test.returns_25(myMock.Object);
// Assert
Assert.AreEqual(25, return_number);
}
Related
I am trying to test the following GetNumber public method using NUnit.
public GetNumber()
{
var numberOfUsers = GetNumberOfUsers();
var number = numberOfUsers + 1;
return number;
}
To test it fully I need the private GetNumberOfUsers method to return a specific value during the execution of the test e.g. 0 or 1. How can I set up my test so that GetNumberOfUsers returns the values that I want?
The logic of the test will be something like the below:
[Test]
public void GetNumberTest()
{
//setup GetNumberOfUsers so that it returns 0
var result = object.GetNumber();
Assert.AreEqual(1, result);
}
You can't. You should be aiming to test your public interface. You haven't given enough detail about where GetNumberOfUsers gets it's result from which makes it difficult to give you the optimum solution. You could make GetNumberOfUsers protected and override it in a subclass. e.g.
public class MyClass
{
public int GetNumbers()
{
var numberOfUsers = GetNumberOfUsers();
}
protected virtual GetNumberOfUsers()
{ // implementation }
}
public class MyClassImplForTesting : MyClass
{
public int NumberOfUsers {get; set;} = 10;
protected overrides GetNumberOfUsers()
{
return NumberOfUsers;
}
}
I'm working on a unit test for a service method, that has dependencies. Simplified:
public class ConditionChecker
{
private SqlConnection _connection;
public bool CanDoSomething()
{
return _connection.State == ConnectionState.Open;
}
}
public class A
{
public ConditionChecker Checker { get; set; }
public bool CanInvokeA()
{
return Checker.CanDoSomething();
}
}
[TestClass]
public class ATests
{
[TestMethod]
public void TestCanInvokeA()
{
// arrange
A a = new A();
ConditionChecker checker = MockRepository.GenerateStub<ConditionChecker>();
checker.Stub(x => x.CanDoSomething()).Return(true);
a.Checker = checker;
// act
bool actual = a.CanInvokeA();
// assert
Assert.AreEqual(true, actual);
}
}
What I want is to completely bypass the implementation of ConditionChecker.CanDoSomething, which is why I stub the call, still I run into a null reference Exception during my test, since the _connection member is not set. What am I doing wrong here?
You just mark your method as virtual, it will work:
public virtual bool CanDoSomething()
{
}
Since behind the scene Rhino Mock will create a dynamic proxy for ConditionChecker, so you need to mark virtual to allow Rhino Mock to override it.
I have a class named "CollectionPager" which has a collection inside that of type List. I have a method "RetrieveList" which takes a "CollectionPager" as input and populates "List" in side that. This method doesn't return any value.
I need to mock a function which calls "RetrieveList". However, since it doesn't return any value, whatever input was fed into Mock is not taken into consideration and this collection(List) always has a count of 0.
Any possible ways to resolve this?
I guess you need the Callback (see also Moq quickstart) method to setup some logic when mocking a void function.
Here is sample test which demonstrates the usage:
var mock = new Mock<IRetrieveListService>();
mock.Setup(m => m.RetrieveList(It.IsAny<CollectionPager>()))
.Callback<CollectionPager>(p =>
{
p.List.Add("testItem1");
p.List.Add("testItem2");
});
var sut = new OtherService(mock.Object);
sut.SomeMethodToTest();
Assuming your classes looks like something like these:
public class CollectionPager
{
public CollectionPager()
{
List = new List<string>();
}
public List<string> List { get; private set; }
}
public interface IRetrieveListService
{
void RetrieveList(CollectionPager pager);
}
public class RetrieveListService : IRetrieveListService
{
public void RetrieveList(CollectionPager pager)
{
pager.List.Add("item1");
pager.List.Add("item2");
}
}
public class OtherService
{
private readonly IRetrieveListService retrieveListService;
public OtherService(IRetrieveListService retrieveListService)
{
this.retrieveListService = retrieveListService;
}
public void SomeMethodToTest()
{
var collectionPager = new CollectionPager();
retrieveListService.RetrieveList(collectionPager);
// in your test collectionPager.Item contains: testItem1, testItem2
}
}
I am using Moq library for unit testing. Now what i want is that when I access my object for the first time it should return null, and when i access this on second time it should return something else.
here is my code
var mock = new Mock<IMyClass>();
mock.Setup(?????);
mock.Setup(?????);
var actual = target.Method(mock.object);
in my method i am first checking that whether mock object is null or not, if it is null then do initialize it and then do some calls on it.
bool Method(IMyClass myObj)
{
if (myObj != null)
return true;
else
{
myObj = new MyClass();
bool result = myObj.SomeFunctionReturningBool();
return result;
}
}
what to do setup for mock object,
Also i need to know how to mock this line
bool result = myObj.SomeFunctionReturningBool();
It sounds like you are trying to run two tests with one test method - maybe it would be better to split the tests into two?
You also want to initialise a new object if the method is passed null. To test this, I suggest creating a factory object responsible for creating instances of MyClass. The new code would look like:
interface IMyClassFactory
{
IMyClass CreateMyClass();
}
bool Method(IMyClass myObj, IMyClassFactory myClassFactory)
{
if (myObj != null)
{
return true;
}
myObj = myClassFactory.CreateMyClass();
return myObj.SomeFunctionReturningBool();
}
Then the tests would look like:
[Test]
public void Method_ShouldReturnTrueIfNotPassedNull()
{
Assert.That(target.Method(new MyClass()), Is.True);
}
[Test]
public void Method_ShouldCreateObjectAndReturnResultOfSomeFunctionIfPassedNull()
{
// Arrange
bool expectedResult = false;
var mockMyClass = new Mock<IMyClass>();
mockMyClass.Setup(x => x.SomeFunctionReturningBool()).Returns(expectedResult);
var mockMyFactory = new Mock<IMyClassFactory>();
mockMyFactory.Setup(x => x.CreateMyClass()).Returns(mockMyClass.Object);
// Act
var result = target.Method(null, mockMyFactory.Object);
// Assert
mockMyClass.Verify(x => x.SomeFunctionReturningBool(), Times.Once());
mockMyFactory.Verify(x => x.CreateMyClass(), Times.Once());
Assert.That(result, Is.EqualTo(expectedResult));
}
Here the factory pattern has been used to pass in an object which can create objects of IMyClass type, and then the factory itself has been mocked.
If you do not want to change your method's signature, then create the factory in the class's constructor, and make it accessible via a public property of the class. It can then be overwritten in the test by the mock factory. This is called dependency injection.
Moq - Return null - This working example simply illustrates how to return null using Moq. While the line of code is required is the commented line below, a full working example is provided below.
// _mockShopService.Setup(x => x.GetProduct(It.IsAny<string>())).Returns(() => null);
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
public class Product
{
public string Id { get; set; }
public string Name { get; set; }
}
public interface IShopService
{
Product GetProduct(string productId);
}
public class ShopService : IShopService
{
public Product GetProduct(string productId)
{
if (string.IsNullOrWhiteSpace(productId))
{
return new Product();
}
return new Product { Id = "8160807887984", Name = "How to return null in Moq" };
}
}
public class Shop
{
private static IShopService _shopService;
public Shop(IShopService shopService)
{
_shopService = shopService;
}
public Product GetProduct(string productId)
{
Product product = _shopService.GetProduct(productId);
return product;
}
}
[TestClass]
public class ShopTests
{
Mock<IShopService> _mockShopService;
[TestInitialize]
public void Setup()
{
_mockShopService = new Mock<IShopService>();
}
[TestMethod]
public void ShopService_GetProduct_Returns_null()
{
//Arrange
Shop shop = new Shop(_mockShopService.Object);
//This is how we return null --- all other code above is to bring this line of code home
_mockShopService.Setup(x => x.GetProduct(It.IsAny<string>())).Returns(() => null);
//Act
var actual = shop.GetProduct(It.IsAny<string>());
//Assert
Assert.IsNull(actual);
}
}
To mock a result value you can do simply:
mock.Setup(foo => foo.SomeFunctionReturningBool()).Returns(true); // or false :)
for the other question, just pass null in the unit test instead of passing mock.object and your unit test cover that too. So you basically create two unit test one with:
var actual = target.Method(mock.object);
and the other one with:
var actual = target.Method(null);
Currently your SUT is tight-coupled with MyClass implementation. You can't mock objects which are instantiated with new keyword inside your SUT. Thus you cannot test your SUT in isolation, and your test is not unit test anymore. When implementation of MyClass.SomeFunctionReturningBool will change (it will return true instead of false), tests of your SUT will fail. This shouldn't happen. Thus, delegate creation to some dependency (factory) and inject that dependency to your SUT:
[Test]
public void ShouldReturnTrueWhenMyClassIsNotNull()
{
Mock<IMyClassFactory> factory = new Mock<IMyClassFactory>();
Mock<IMyClass> myClass = new Mock<IMyClass>();
var foo = new Foo(factory.Object);
Assert.True(foo.Method(myClass.Object));
}
[Test]
public void ShouldCreateNewMyClassAndReturnSomeFunctionValue()
{
bool expected = true;
Mock<IMyClass> myClass = new Mock<IMyClass>();
myClass.Setup(mc => mc.SomeFunctionReturningBool()).Returns(expected);
Mock<IMyClassFactory> factory = new Mock<IMyClassFactory>();
factory.Setup(f => f.CreateMyClass()).Returns(myClass.Object);
var foo = new Foo(factory.Object);
Assert.That(foo.Method(null), Is.EqualTo(expected));
factory.VerifyAll();
myClass.VerifyAll();
}
BTW assignment new value to method parameter does not affect reference which you passed to method.
Implementation:
public class Foo
{
private IMyClassFactory _factory;
public Foo(IMyClassFactory factory)
{
_factory = factory;
}
public bool Method(IMyClass myObj)
{
if (myObj != null)
return true;
return _factory.CreateMyClass().SomeFunctionReturningBool();
}
}
You can use TestFixture with parameter. this test will run two times and different type value.
using NUnit.Framework;
namespace Project.Tests
{
[TestFixture(1)]
[TestFixture(2)]
public class MyTest
{
private int _intType;
public MyTest(int type)
{
_intType = type;
}
[SetUp]
public void Setup()
{
if (_intType==1)
{
//Mock Return false
}
else
{
//Mock Return Value
}
}
}
}
public interface IServiceInvoker
{
R InvokeService<T, R>(Func<T, R> invokeHandler) where T : class;
}
public class MediaController : Controller
{
private IServiceInvoker _serviceInvoker;
public MediaController(IServiceInvoker serviceInvoker)
{
_serviceInvoker = serviceInvoker;
}
public JsonResult GetAllMedia()
{
var media = _serviceInvoker.InvokeService<IMediaService, List<MediaBase>>(proxy => proxy.GetAllMediaInJson());
JsonResult jsonResult = new JsonResult();
jsonResult.Data = media;
jsonResult.JsonRequestBehavior = JsonRequestBehavior.AllowGet;
return jsonResult;
}
[TestClass]
public class MediaControllerTests
{
[TestMethod]
public void GetAllMedia()
{
JsonResult data;
var serviceInvoker = MockRepository.GenerateStub<IServiceInvoker>();
var media = CreateSeveralMedia();
serviceInvoker.Stub(c => c.InvokeService<IMediaService, List<MediaBase>>(p => p.GetAllMediaInJson())).Return(media);
data = new MediaController(serviceInvoker).GetAllMedia();
serviceInvoker.VerifyAllExpectations();
Assert.IsNotNull(data);
}
}
I am stubbing the service and returning a collection. When I run this test, media is null. Any idea, how can I set expectations on this mock ?
Just found a solution. It seems to be a little ugly, but it is the first iteration only probably more elegant version will appear soon. The idea is to create another stub and match Func<> against it:
I will provide code for my use case:
[Theory]
[InlineData(342, 31129, 3456)]
public void should_call_service_invoker_and_return_result(int number1, int number2, int expected)
{
var calculator = MockRepository.GenerateStub<ICalculator>();
calculator.Stub(_ => _.Add(number1, number2)).Return(expected);
var serviceInvoker = MockRepository.GenerateStub<ServiceInvoker<ICalculator>>();
serviceInvoker
.Stub(_ => _.Invoke(Arg<Func<ICalculator, int>>.Matches(d => d(calculator) == calculator.Add(number1, number2))))
.Return(expected);
var serviceConsumer = new ServiceConsumer(serviceInvoker);
var actual = serviceConsumer.GetAddResultFor(number1, number2);
Assert.Equal(expected, actual);
}
xUnit + extensions is used as testing framework. Please ignore Theory and InlineData stuff -- it is just another way to get rid of unnecessary test setup.
Here is the code of SUT:
public class ServiceConsumer
{
private readonly ServiceInvoker<ICalculator> serviceInvoker;
public ServiceConsumer(ServiceInvoker<ICalculator> serviceInvoker)
{
this.serviceInvoker = serviceInvoker;
}
public int GetAddResultFor(int number1, int number2)
{
return serviceInvoker.Invoke(_ => _.Add(number1, number2));
}
}
public class ServiceInvoker<T>
{
public virtual R Invoke<R>(Func<T, R> func)
{
throw new NotImplementedException();
}
}
public interface ICalculator
{
int Add(int number1, int number2);
}
Hope this will be helpful. Any suggestions of how to add more beauty are welcome :)
The lambda in your unit test compiles into a class-level method (a method inside your unit test). Inside your controller, a different lambda compiles into a class-level method (inside the controller). The stub set up in your unit test doesn't match the stub being executed in your controller, so Rhino Mocks returns a default (null). More here: http://groups.google.com/group/rhinomocks/browse_frm/thread/a33b165c16fc48ee?tvc=1