I've just started to implement unit tests (using xUnit and Moq) on an already established project of mine. The project extensively uses dependency injection via the unity container.
I have two services A and B. Service A is the one being tested in this case. Service A calls B and gives it a delegate to an internal function. This 'callback' is used to notify A when a message has been received that it must handle.
Hence A calls (where b is an instance of service B):
b.RegisterHandler(Guid id, Action<byte[]> messageHandler);
In order to test service A, I need to be able to call messageHandler, as this is the only way it currently accepts messages.
Can this be done using Moq? ie. Can I mock service B, such that when RegisterHandler is called, the value of messageHandler is passed out to my test?
Or do I need to redesign this? Are there any design patterns I should be using in this case? Does anyone know of any good resources on this kind of design?
You can get an instance of the callback (or any other input parameter) by using the Callback (the name similarity is incidental) method on the Mock:
[TestMethod]
public void Test19()
{
Action<byte[]> callback = null;
var bSpy = new Mock<IServiceB>();
bSpy.Setup(b => b.RegisterHandler(It.IsAny<Guid>(), It.IsAny<Action<byte[]>>()))
.Callback((Guid g, Action<byte[]> a) => callback = a);
var sut = new ServiceA(bSpy.Object);
sut.RegisterCallback();
Assert.AreEqual(sut.Do, callback);
}
This works when ServiceA is defined as this:
public class ServiceA
{
private readonly IServiceB b;
public ServiceA(IServiceB b)
{
if (b == null)
{
throw new ArgumentNullException("b");
}
this.b = b;
}
public void RegisterCallback()
{
this.b.RegisterHandler(Guid.NewGuid(), this.Do);
}
public void Do(byte[] bytes)
{
}
}
Yes you can setup the Moq object to respond to expected and unexpected operations.
Here's a Visual Studio Unit Test example...
[TestMethod]
public void MyTest()
{
var moqObject = new Mock<ServiceB>();
// Setup the mock object to throw an exception if a certain value is passed to it...
moqObject.Setup(b => b.RegisterHandle(unexpectedValue).Throws(new ArgumentException());
// Or, setup the mock object to expect a certain method call...
moqObject.Setup(b => b.RegisterHandle(expectedValue));
var serviceA = new ServiceA(moqObject.Object);
serviceA.DoSomethingToTest();
// This will throw an exception if an expected operation didn't happen...
moqObject.VerifyAll();
}
Related
I been trying to figure out how i can unit test service and so far have got nowhere.
I am using xUnit and NSubstitute (as advised by friends), below is the simple test that i want to run (which fails currently).
public class UnitTest1
{
private readonly RallyService _rallyService;
public UnitTest1(RallyService rallyService)
{
_rallyService= rallyService;
}
[Fact]
public void Test1()
{
var result = _rallyService.GetAllRallies();
Assert.Equal(2, result.Count());
}
}
My rally service class makes a simple call to the db to get all Rally entites and returns those:
public class RallyService : IRallyService
{
private readonly RallyDbContext _context;
public RallyService(RallyDbContext context)
{
_context = context;
}
public IEnumerable<Rally> GetAllRallies()
{
return _context.Rallies;
}
}
Any guidance would be appreciated.
Since you use .NET Core, I assume you also use Entity Framework Core. While it was possible to mock most of the operations in the previous EF version, however the EF Core suggests to use in-memory database for unit testing. I.e. you don't need to mock RallyDbContext, hence NSubstitute is not needed for this particular test. You would need NSubstitute to mock the service when testing a controller or application using the service.
Below is your Test1 written using in-memory database.
public class UnitTest1
{
private readonly DbContextOptions<RallyDbContext> _options;
public UnitTest1()
{
// Use GUID for in-memory DB names to prevent any possible name conflicts
_options = new DbContextOptionsBuilder<RallyDbContext>()
.UseInMemoryDatabase(Guid.NewGuid().ToString())
.Options;
}
[Fact]
public async Task Test1()
{
using (var context = new RallyDbContext(_options))
{
//Given 2 records in database
await context.AddRangeAsync(new Rally { Name = "rally1" }, new Rally { Name = "rally2" });
await context.SaveChangesAsync();
}
using (var context = new RallyDbContext(_options))
{
//When retrieve all rally records from the database
var service = new RallyService(context);
var rallies = service.GetAllRallies();
//Then records count should be 2
Assert.Equal(2, rallies.Count());
}
}
}
A working test application with this unit test is in my GitHub for your reference. I used SQL Express in the actual app.
I don't think it is standard to have a unit test constructor with a parameter. The unit test runner will new up this class, and unless you are using something that will auto-inject that parameter I think the test will fail to run.
Here is a standard fixture layout:
public class SampleFixture {
[Fact]
public void SampleShouldWork() {
// Arrange stuff we need for the test. This may involved configuring
// some dependencies, and also creating the subject we are testing.
var realOrSubstitutedDependency = new FakeDependency();
realOrSubstitutedDependency.WorkingItemCount = 42;
var subject = new Subject(realOrSubstitutedDependency);
// Act: perform the operation we are testing
var result = subject.DoWork();
// Assert: check the subject's operation worked as expected
Assert.Equal(42, result);
}
[Fact]
public void AnotherTest() { /* ... */ }
}
If you need a common setup between tests, you can use a parameterless constructor and do common initialisation there.
In terms of the specific class you are trying to test, you need to make sure your RallyDbContext is in a known state to repeatably and reliably test. You may want to look up answers specific to testing Entity Framework for more information.
I want to create an instance of class A which inherits class StatelessService in my unit test. But I can't. I've tried everything: mocking dependencies, implementing my own contexts and etc.
When I try to create an instance, StatelessService throws NullReferenceException somewhere inside.
Can it be done at all?
class A : StatelessService
{
public A(StatelessServiceContext context) : base(context /* Here will be thrown NullReferenceException */)
{
// It will never even get there.
}
}
class UnitTest
{
public void TestMethod()
{
var activationContext = MOCK<ICodePackageActivationContext>();
var context = new StatelessServiceContext(..., activationContext, ...);
var a = new A(context); // Here will be thrown an exception.
}
}
It can be done. But instead of re inventing the wheel, have a look at service fabric mocks https://github.com/loekd/ServiceFabric.Mocks
It contains useful helpers for exactly your type of scenario.
I am assigned to add unit test code coverage to a 15 years old legacy project which is not using IoC and 0 unit test. I am not allowed to refactor the code since it works perfect fine on production, management does not want other teams get involved for refactoring such as QA testing, etc.
Service class has a performService method has following code
public void performService(requestMessage, responseMessage) {
UserAccount userAccount = requestMessage.getUserAccount();
GroupAccount groupAccount = requestMessage.getGroupAccount();
Type type = requestMessage.getType();
StaticServiceCall.enroll(userAccount, groupAccount, type);
response.setStatus(Status.SUCCESS);
}
This StaticServiceCall.enroll method is calling remote service. My unit test is
#RunWith(PowerMockRunner.class)
#PrepareForTest(StaticServiceCall.class)
public class EnrollmentServiceTest {
#Test
public void testPerformService() {
mockStatic(StaticServiceCall.class);
doNothing().when(StaticServiceCall.enroll(any(UserAccount.class), any(GroupAccount.class), any(Type.class)));
service.performService(requestMessage, responseMessage);
assertEquals("Enrollment should be success, but not", Status.SUCCESS, response.getStatus);
}
Eclipse complains with The method when(T) in the type Stubber is not applicable for the arguments (void)
Eclipse stops complain if test code change to
mockStatic(StaticServiceCall.class);
doNothing().when(StaticServiceCall.class);
StaticServiceCall.enroll(any(UserAccount.class), any(GroupAccount.class), any(Type.class));
service.performService(requestMessage, responseMessage);
assertEquals("Enrollment should be success, but not", Status.SUCCESS, response.getStatus);
Test case failed with UnfinishedStubbingException. I am using powermock 1.6.6
There is a misconception on your end. You think that you need to say that doNothing() should do nothing.
That is not necessary! As these lines
#PrepareForTest(StaticServiceCall.class) ... and
mockStatic(StaticServiceCall.class);
are sufficient already.
You want to prevent the "real" content of that static method to run when the method is invoked during your test. And that is what mockStatic() is doing.
In other words: as soon as you use mockStatic() the complete implementation of the real class is wiped. You only need to use when/then/doReturn/doThrow in case you want to happen something else than nothing.
Meaning: just remove that whole doNothing() line!
#GhostCat - Thank you for your answer, it solved problem, my misconception is coming from this test case
#Test
public void testEnrollmentServiceSuccess() {
RequestMessage requestMessage = new RequestMessage();
requestMessage.setName("ENROLL");
ResponseMessage responseMessage = new ResponseMessage();
EnrollmentService mockService = mock(EnrollmentService.class);
mockService.performService(any(RequestMessage.class), any(ResponseMessage.class));
mockStatic(ClientManager.class);
when(ClientManager.isAuthenticated()).thenReturn(true);
ServiceImpl service = new ServiceImpl();
service.performService(requestMessage, responseMessage);
verify(mockService).performService(any(RequestMessage.class), any(ResponseMessage.class));
}
Here is the code snippet of ServiceImpl class based name of the request message calling different service class
public void performService(RequestMessage request, ResponseMessage response) {
try {
if (request == null) {
throw new InvalidRequestFormatException("null message");
}
if (!ClientManager.isAuthenticated()) {
throw new ServiceFailureException("not authenticated");
}
// main switch for known services
if ("ENROLL".equals(request.getName())) {
service = new EnrollmentService();
service.performService(request, response);
} else if ("VALIDATE".equals(request.getName())) {
...
Although the test passed,real implementation in EnrollmentService got called and exceptions thrown due to barebone RequestMessage object, then I googled out doNothing, thanks again for your clarification
I am trying to mock my class that is under test, so that I can callbase on individual methods when testing them. This will allow me to test the method setup as callbase only, and all other methods (of the same class) called from within the test method will be mocked.
However, I am unable to do this for the methods that do not return a value. The intellisense just doesn't display the option of callbase, for methods that do not return value.
Is this possible?
The Service Class:
public class Service
{
public Service()
{
}
public virtual void StartProcess()
{
//do some work
string ref = GetReference(id);
//do more work
SendReport();
}
public virtual string GetReference(int id)
{
//...
}
public virtual void SendReport()
{
//...
}
}
Test Class setup:
var fakeService = new Mock<Service>();
fakeService.Setup(x => x.StartProcess());
fakeService.Setup(x => x.GetReference(It.IsAny<int>())).Returns(string.Empty);
fakeService.Setup(x => SendReport());
fakeService.CallBase = true;
Now in my test method for testing GetReference I can do this:
fakeService.Setup(x => x.GetReference(It.IsAny<int>())).CallBase();
but when i want to do the same for StartProcess, .CallBase is just not there:
fakeService.Setup(x => x.StartProcess()).CallBase();
it becomes available as soon as i make the method to return some thing, such a boolean value.
First of all, your mock will not work because methods on Service class are not virtual. When this is a case, Moq cannot intercept calls to insert its own mocking logic (for details have a look here).
Setting mock.CallBase = true instructs Moq to delegate any call not matched by explicit Setup call to its base implementation. Remove the fakeService.Setup(x => x.StartProcess()); call so that Moq can call base implementation.
Here is my situation:
I want to test on the "HasSomething()" function, which is in the following class:
public class Something
{
private object _thing;
public virtual bool HasSomething()
{
if (HasSomething(_thing))
return true;
return false;
}
public virtual bool HasSomething(object thing)
{
....some algo here to check on the object...
return true;
}
}
So, i write my test to be like this:
public void HasSomethingTest1()
{
MockRepository mocks = new MockRepository();
Something target = mocks.DynamicMock(typeof(Something)) as Something;
Expect.Call(target.HasSomething(new Object())).IgnoreArguments().Return(true);
bool expected = true;
bool actual;
actual = target.HasSomething();
Assert.AreEqual(expected, actual);
}
Is my test written correctly?
Please help me as i can't even get the result as expected. the "HasSomething(object)" just can't be mock in that way. it did not return me 'true' as being set in expectation.
Thanks.
In response to OP's 'answer': Your main problem is that RhinoMocks does not mock members of classes - instead it creates mock classes and we can then set expectations and canned responses for its members (i.e. Properties and Functions). If you attempt to test a member function of a mock/stub class, you run the risk of testing the mocking framework rather than your implementation.
For the particular scenario of the logical path being dependent on the return value of a local (usually private) function, you really need an external dependency (another object) which would affect the return value that you require from that local function. For your code snippet above, I would write the test as follows:
[Test]
public void TestHasSomething()
{
// here I am assuming that _thing is being injected in via the constructor
// you could also do it via a property setter or a function
var sut = new Something(new object());
Assert.IsTrue(sut.HasSomething);
}
i.e. no mocking required.
This is one point of misunderstanding that I often had in the past with regards to mocking; we mock the behaviour of a dependency of the system under test (SUT). Something like: the SUT calls several methods of the dependency and the mocking process provides canned responses (rather than going to the database, etc) to guide the way the logic flows.
A simple example would be as follows (note that I have used RhinoMocks AAA syntax for this test. As an aside, I notice that the syntax that you are using in your code sample is using the Record-Replay paradigm, except that it isn't using Record and Replay! That would probably cause problems as well):
public class SUT
{
Dependency _depend
public SUT (Dependency depend)
{
_depend = depend;
}
...
public int MethodUnderTest()
{
if (_depend.IsReady)
return 1;
else
return -1;
}
}
...
[Test]
public void TestSUT_MethodUnderTest()
{
var dependency = MockRepository.GenerateMock<Dependency>();
dependency.Stub(d => d.IsReady).Return(true);
var sut = new SUT(dependency);
Assert.AreEqual(1, sut.MethodUnderTest());
}
And so the problem that you have is that you are attempting to test the behaviour of a mocked object. Which means that you aren't actually testing your class at all!
In a case like this, your test double should be a derived version of class Something. Then you override the method HasSomething(object) and ensure that HasSomething() calls your one.
If I understand correctly, you are actually interested in testing the method HasDynamicFlow (not depicted in your example above) without concerning yourself with the algorithm for HasSomething.
Preet is right in that you could simply subclass Something and override the behavior of HasSomething to short-circuit the algorithm, but that would require creating some additional test-dummy code which Rhino is efficient at eliminating.
Consider using a Partial Mock Stub instead of a Dynamic Mock. A stub is less strict and is ideal for working with Properties. Methods however require some extra effort.
[Test]
public void CanStubMethod()
{
Foo foo = MockRepository.GenerateStub<Foo>();
foo.Expect(f => f.HasDynamicFlow()).CallOriginalMethod(OriginalCallOptions.NoExpectation);
foo.Expect(f => f.HasSomething()).CallOriginalMethod(OriginalCallOptions.NoExpectation);
foo.Expect(f => f.HasSomething(null)).IgnoreArguments().Return(true);
Assert.IsTrue(foo.HasDynamicFlow());
}
EDIT: added code example and switched Partial Mock to Stub