I have the follwing two classes ClassA and ClassB.
To focus on: ClassB implements a factory of ClassA.
I want to test ClassB. So how can I (or would you) mock a factory of ClassA, sothat ClassB can instantiate a mock of ClassA and access its mocked function .ReturnString()?
public class ClassA : IClassA
{
readonly int _number;
public ClassA(int number)
{
_number = number;
}
public string ReturnString()
{
return _number.ToString();
}
}
public class ClassB : IClassB
{
int _exampleValue;
readonly Func<int, IClassA> _classAFactory;
public ClassB(Func<int, IClassA> classAFactory)
{
_classAFactory = classAFactory;
}
public string ExampleFct()
{
_exampleValue = 5;
IClassA classA = _classAFactory(_exampleValue)
return classA.ReturnString();
}
}
public class TestClassB
{
[Fact]
public void TestClassBReturnsCorrectString()
{
// Arrange
var mockClassAFact = ???
IClassB classB = new ClassB(mockClassAFact);
// Act
string aString = classB.ExampleFct();
// Assert
Assert.True(aString == "5");
}
}
As I am using "Autofac" as a base for IoC there might be a specific solution for this?
Thank you for any help!
mock the dependency (interface) as desired and create a delegate for the "factory" when arranging the test
[Fact]
public void TestClassBReturnsCorrectString() {
// Arrange
string expected = "5"
IClassA mockClassA = Mock.Of<IClassA>(_ => _.ReturnString() == expected);
int value = 5;
Func<int, IClassA> mockClassAFact =
number => number == value ? mockClassA : throw new InvalidArgumentException();
IClassB subject = new ClassB(mockClassAFact);
// Act
string actual = subject.ExampleFct();
// Assert
Assert.True(actual == expected);
}
Note: The above example uses MOQ to mock the IClassA dependency and creates a factory delegate to be used to exercised the test.
"Autofac" in this case is an implementation detail that has no actual bearing on this isolated unit test.
Related
I've been reading around and I can't seem to find a case that matches the behavior I want with Moq.
I want to mock a specific method (which is interfacing with an external API) of a class that I want to test. The problem is that, as I understand it, once the class is .Create<T>, you cannot .Setup()... any method on it.
Here is an example:
public class ClassA
{
public void ConfigureExpansion()
{
var classB = new ClassB();
var data = GetExternalData(); // I want to mock this
//data is used in the code
classB.TaskB(data); // I want to mock this
}
public string GetExternalData()
{
return data...
}
}
public class ClassB
{
public void TaskB(String myData)
{
//Does some work
}
}
[TestMethod]
public void Test()
{
using (var mock = AutoMock.GetLoose())
{
mock.Mock<IClassB>().Setup(x => x.TaskB(It.IsAny<string>()));
var cls = mock.Create<ClassA>();
cls.Setup(x => x.GetExternalData(It.IsAny<string>())).Return("MyData"); // <--- This is not valid, but represents what I am trying to do.
//act
cls.ConfigureExpansion();
mock.Mock<IClassB>().Verify(x => x.TaskB(), Times.Once);
}
}
I tried to set up a mock for the interface of my class under test, but the cls won't call it:
[TestMethod]
public void Test()
{
using (var mock = AutoMock.GetLoose())
{
mock.Mock<IClassA>().Setup(x => x.GetExternalData(It.IsAny<string>())).Return("MyData"); //<--- Mocking the method here is not detected by the cls below
mock.Mock<IClassB>().Setup(x => x.TaskB(It.IsAny<string>()));
var cls = mock.Create<ClassA>();
//act
cls.ConfigureExpansion();
mock.Mock<IClassB>().Verify(x => x.TaskB(), Times.Once);
}
}
I've also tried instantiating my class-under-test and when I do it like this, it doesn't take the mocks (ClassB) into consideration:
[TestMethod]
public void Test()
{
using (var mock = AutoMock.GetLoose())
{
mock.Mock<IClassA>().Setup(x => x.GetExternalData(It.IsAny<string>())).Return("MyData"); //<--- Mocking the method here is not detected by the cls below
mock.Mock<IClassB>().Setup(x => x.TaskB(It.IsAny<string>()));
var cls = new ClassA();
//act
cls.ConfigureExpansion();
mock.Mock<IClassB>().Verify(x => x.TaskB(), Times.Once);
}
}
I would really appreciate any insights about this,
Thank you
Here is one approach for your problem. If you want to test ConfigureExpansion of ClassA, you have to mock the dependencies used in that method, which is ClassB. You cannot mock GetExternalData of ClassA because ClassA is the class under test now. You may have to refactor your classes in a way so that there is a ClassUnderTest which creates both instances of ClassA and ClassB using dependency injection. Then, you can use Moq to mock the interfaces IClassA and IClassB to test the ConfigureExpansion.
public class ClassUnderTest
{
private readonly IClassA _classA;
private readonly IClassB _classB;
public ClassUnderTest(IClassA classA, IClassB classB)
{
this._classA = classA;
this._classB = classB;
}
public void ConfigureExpansion()
{
var data = this._classA.GetExternalData();
this._classB.TaskB(data);
}
}
public interface IClassA
{
string GetExternalData();
}
public class ClassA : IClassA
{
public string GetExternalData()
{
return "some data";
}
}
public interface IClassB
{
void TaskB(string myData);
}
public class ClassB : IClassB
{
public void TaskB(string myData)
{
//Does some work
}
}
The test method can be:
[TestMethod]
public void Test()
{
using (var mock = AutoMock.GetLoose())
{
var mockClassA = mock.Mock<IClassA>();
var mockClassB = mock.Mock<IClassB>();
mockClassA.Setup(x => x.GetExternalData()).Returns("MyData");
var cls = new ClassUnderTest(mockClassA.Object, mockClassB.Object);
//act
cls.ConfigureExpansion();
mockClassB.Verify(x => x.TaskB(It.IsAny<string>()), Times.Once);
}
}
I want to mock only some methods of a class and call the real implementation for other methods.
I have my sut class Test where the Runner class is injected in the constructor. This injected class has again a injected other class RunnerParam in the constructor.
The code is a simplified case of my real classes in trying to have only the basics.
[Fact]
public void Test()
{
var fixture = new Fixture().Customize(new AutoMoqCustomization());
var paramMock = fixture.Freeze<Mock<IRunnerParam>>();
paramMock.Setup(x => x.Multiplicator()).Returns(2);
var classMock = fixture.Freeze<Mock<IRunner>>();
classMock.Setup(x => x.Run()).Returns(5);
var test = fixture.Create<Test>();
var result = test.StartRunning(); // should be 5
var result2 = test.StartRunningImplementation(5); // should be 500
}
Supporting members
public interface IRunnerParam
{
int Multiplicator();
}
public class RunnerParam : IRunnerParam
{
public virtual int Multiplicator()
{
return 20;
}
}
public interface IRunner
{
int Run();
int RunImplementation(int param);
}
public class Runner : IRunner
{
protected virtual RunnerParam MultiParam { get; set; }
public Runner(RunnerParam multiParam)
{
MultiParam = multiParam;
}
public virtual int Run()
{
return 10;
}
public int RunImplementation(int param)
{
return 10 * MultiParam.Multiplicator() * param * Run();
}
}
public class Test
{
private readonly IRunner _runner;
public Test(IRunner runner)
{
_runner = runner;
}
public int StartRunning()
{
return _runner.Run();
}
public int StartRunningImplementation(int param)
{
return _runner.RunImplementation(param);
}
}
I want to mock and give a mocked value to the method Run in the class Runner, but to use the real implementation of the method RunImplementation.
I would expect to see for result2 500, but it's 0, meaning that the method is not seen as mocked up. In my eyes that is correct, but the Moq callbase is equal to true, so the real implementation should be taken, but it isn't.
What am I missing here?
In the shown simplified example, Test is only dependent on IRunner
private readonly IRunner _runner;
public Test(IRunner runner)
{
_runner = runner;
}
So that is all that needs to be mocked if the intention was to test Test class in isolation.
//...
var classMock = fixture.Freeze<Mock<IRunner>>();
classMock.Setup(x => x.Run()).Returns(5);
classMock.Setup(x => x.RunImplementation(It.IsAny<int>())).Returns(500);
//...
If Runner class is to be also tested in isolation, then a mocked RunnerParam would be needed to satisfy its dependencies.
It should however be dependent on the abstraction (interface) and not the concretion (implementation).
protected virtual IRunnerParam MultiParam { get; set; }
public Runner(IRunnerParam multiParam) {
MultiParam = multiParam;
}
This simplifies the isolated test as described in the original question
I want to mock and give a mocked value to the method Run in the class Runner, but to use the real implementation of the method RunImplementation.
//Arrange
var fixture = new Fixture().Customize(new AutoMoqCustomization());
var runnerParam = fixture.Freeze<Mock<IRunnerParam>>()
.Setup(_ => _.Multiplicator())
.Returns(2);
var subjectMock = fixture.Freeze<Mock<Runner>>();
subjectMock.CallBase = true;
subjectMock.Setup(_ => _.Run()).Returns(5);
int expected = 500;
Runner sut = subjectMock.Object;
//Act
var actual = sut.RunImplementation(5); // should be 500
//Assert
actual.Should().Be(expected);
I want to spy return value of a mocked method of a mocked interface in NSubstitute. I get return value of Received function but it always returns null.
public interface IFactory
{
object Create();
}
public interface IMockable
{
object SomeMethod();
}
public class Mockable : IMockable
{
private readonly IFactory factory;
public Mockable(IFactory factory)
{
this.factory = factory;
}
public object SomeMethod()
{
object newObject = factory.Create();
return newObject;
}
}
public class TestClass
{
[Fact]
void TestMethod()
{
var factory = Substitute.For<IFactory>();
factory.Create().Returns(x => new object());
IMockable mockable = new Mockable(factory);
object mockableResult = mockable.SomeMethod();
object factoryResult = factory.Received(1).Create();
Assert.Equal(mockableResult, factoryResult);
}
}
I expect that mockableResult and factoryResult be equal but factoryResult is null.
That is because you are using it incorrectly. Received is an assertion on the called method. It does not return a usable value from mocked members.
Review the follow modified version of your test that behaves as you would have expected.
public class TestClass {
[Fact]
void TestMethod() {
//Arrange
object factoryResult = new object(); //The expected result
var factory = Substitute.For<IFactory>();
factory.Create().Returns(x => factoryResult); //mocked factory should return this
IMockable mockable = new Mockable(factory);
//Act
object mockableResult = mockable.SomeMethod(); //Invoke subject under test
//Assert
factory.Received(1).Create(); //assert expected behavior
Assert.Equal(mockableResult, factoryResult); //objects should match
}
}
I'm new to Moq and I would like to mock certain part of my method to test the business logic but having problem to mock the GetCountry method. Below is the code that I used as sample.
public class Class1
{
public void Process()
{
MyClass foo = new MyClass();
var o = foo.GetCountry(); //I would like to mock this part.
//Business Logic here
}
}
public class MyClass : IFoo
{
public List<string> GetCountry()
{
//Get the data from Database.. someone will do this
throw new NotImplementedException();
}
}
Below is my Test Code that I used.
[TestMethod]
public void TestMethod2()
{
var mock = new Moq.Mock<IFoo>();
mock.Setup(m => m.GetCountry()).Returns(new List<string> { "America", "Philippines", "Japan" });
ClassLibrary1.Class1 foo = new ClassLibrary1.Class1();
//still called the not implemented exception
foo.Process();
}
Your code currently doesn't have an easy way to replace one implementation to another. Try this approach:
public class Class1
{
// Instead of using a concrete class, use an interface
// also, promote it to field
IFoo _foo;
// Create a constructor that accepts the interface
public Class1(IFoo foo)
{
_foo = foo;
}
// alternatively use constructor which provides a default implementation
public Class1() : this(new MyClass())
{
}
public void Process()
{
// Don't initialize foo variable here
var o = _foo.GetCountry();
//Business Logic here
}
}
If you have such setup it is quite easy to mock it using your code:
[TestMethod]
public void TestMethod2()
{
var mock = new Moq.Mock<IFoo>();
mock.Setup(m => m.GetCountry()).Returns(new List<string> { "America", "Philippines", "Japan" });
// Pass mocked object to your constructor:
ClassLibrary1.Class1 foo = new ClassLibrary1.Class1(mock.Object);
foo.Process();
}
I am trying mock internal method in the same class.But my mocking fails.
Here is my code.
Interface
public interface IStudentService
{
int GetRank(int studentId);
IList<Subject> GetSubjects(int studentId);
}
Implementation
public class StudentService : IStudentService
{
private readonly IStudentRepository _studentRepository;
private readonly ISubjectRepository _subjectRepository;
public StudentService(IStudentRepository studentRepository, ISubjectRepository subjectRepository)
{
_studentRepository = studentRepository;
_subjectRepository = subjectRepository;
}
public int GetRank(int studentId)
{
IList<Subject> subjects = GetSubjects(studentId);
int rank = 0;
//
//Calculate Rank
//
return rank;
}
public virtual IList<Subject> GetSubjects(int studentId)
{
return _subjectRepository.GetAll(studentId);
}
}
Unit Test
[TestFixture]
public class StudentServiceTest
{
[SetUp]
public void Setup()
{
}
[TearDown]
public void TearDown()
{
}
[Test]
public void GetRankTest()
{
using (var mock = AutoMock.GetStrict())
{
var mockStudentService = new Mock<IStudentService>();
mockStudentService.Setup(x => x.GetSubjects(1)).Returns(new ServiceResponse<SystemUser>(new List<Subject>{ new AccounProfile(), new AccounProfile()}));
mock.Provide(mockStudentService.Object);
var component = mock.Create<StudentService>();
int rank = component.GetRank(1);
mockStudentService.VerifyAll();
Assert.AreEqual(1, rank, "GetRank method fails");
}
}
}
When I debug the code it is not mocking the GetSubjects method. It actually go inside to that method. I am using Nunit, Moq and Autofac to write unit test.
Thanks In Advance!
There are two solutions.
1. Partial mocking
In this approach you create mock of component you're testing (StudentService) and tell Moq to mock some of its methods (GetSubjects -- to-be-mocked methods must be virtual), while delegating others (GetRank) to base implementation:
Setting mock.CallBase = true instructs Moq to delegate any call not matched by explicit Setup call to its base implementation.
// mockStudentService is not needed, we use partial mock
var service = mock.Create<StudentService>();
service.CallBase = true;
service.Setup(m => m.GetSubjects(1)).Returns(...);
var rank = service.GetRank(1);
// you don't need .VerifyAll call, you didn't not set any expectations on mock
Assert.AreEqual(1, rank, "GetRank method fails");
2. Mocking internal service (ISubjectRepository)
Partial mocks are reserved for special cases. Your case is rather common one. Instead of mocking itself, your component (StudentService) could rely on mocked ISubjectRepository to provide subjects for it:
using (var mock = AutoMock.GetStrict())
{
var subjectRepositoryMock = new Mock<ISubjectRepository>();
subjectRepositoryMock.Setup(x => x.GetSubjects(1)).Returns(...);
mock.Provide(subjectRepositoryMock.Object);
var component = mock.Create<StudentService>();
int rank = component.GetRank(1);
// verify is not needed once again
Assert.AreEqual(1, rank, "GetRank method fails");
}
This code works for. Thank you for everyone for support
[TestFixture]
public class StudentServiceTest
{
private Mock<StudentRepository> _studentRepositoryMock;
private Mock<SubjectRepository> _subjectRepositoryMock;
private Mock<StudentService> _studentServiceMock;
[SetUp]
public void Setup()
{
_studentRepositoryMock = new Mock<StudentService>(MockBehavior.Strict);
_subjectRepositoryMock = new Mock<SubjectRepository>(MockBehavior.Strict);
_studentServiceMock = new Mock<StudentService>(_studentRepositoryMock.Object, _subjectRepositoryMock.Object);
_studentServiceMock.CallBase = true;
}
[TearDown]
public void TearDown()
{
}
[Test]
public void GetRankTest()
{
_studentServiceMock.Setup(x => x.GetSubjects(1)).Returns(...);
int rank = component.GetRank(1);
_studentServiceMock.VerifyAll();
Assert.AreEqual(1, rank, "GetRank method fails");
}
}
I guess your GetSubjects method must be declared virtual, otherwise it cannot be mocked.
public virtual IList<Subject> GetSubjects(int studentId)
{
// code here
}