Dependency Injection with Moq and AutoMoq (AutoFixture) w/ xUnit - unit-testing

I'm writing this because I've tried for a bit to figure this out myself with no luck. Every example I can find for whatever reason seems to suggest that this just works out of the box but whenever I try to do the same, I always get errors. Basically, I have a controller with two properties that are injected via. DI, let's say
public class SomeController
{
private ISomeInterface _i;
private MyConfig _c;
public SomeController(ISomeInterface i, MyConfigContext cxt) // Where cxt is Type of DbContext
{
_i = i;
_c = cxt.Configs.FirstOrDefault();
}
public OkResult PostModel(SomeModel c)
{
// Do things
return Ok();
}
}
And in my tests using xUnit, Moq & AutoFixture I'm trying to avoid having to manually instantiate dependencies B and C:
public class SomeControllerTests
{
private MyDbContext _cxt;
private Fixture _fixture;
public SomeControllerTests()
{
_cxt = GetCxt() // GetCxt() just returns a context instance, nothing special
_fixture = new Fixture();
_fixture.Customize(new AutoMoqCustomization { ConfigureMembers = true });
_fixture.Customizations.Add(
new TypeRelay(
typeof(ISomeInterface),
typeof(SomeConcreteClass)
)
);
}
[Fact, AutoData]
public void PostStatus_ReturnsOk_GivenValidRequest()
{
SomeController c = _fixture.Create<SomeController>();
SomeModel m = _fixture.Create<SomeModel>();
var result = c.PostModel(m);
Asset.IsType<OkResult>(result);
}
}
With the above I am getting a NotImplementedException when I run the tests and it won't tell me what exactly is not being implemented so I have no way of knowing what the issue is. I must be missing something in the docs. I want to use AutoFixture to make my tests more durable but so far it has been a pain trying to use it. I really don't want to have to mock/stub my entire app manually just to run a test. I would ideally like to use the syntax shown in the AutoFixture docs where you put your test-relevant instances in the params of the test and they are created for you but I haven't had any luck with it, like...
[Theory, AutoData]
SomeTestMethod(SomeController c, SomeModel m)
{
var result = c.PostModel(m);
Assert.IsType<OkResult>(result);
}
Thanks for Reading (:

Try to add next attribute and use it instead of AutoData.
using AutoFixture.AutoMoq;
using AutoFixture.Xunit2;
namespace Cats
{
public class AutoMoqDataAttribute : AutoDataAttribute
{
public AutoMoqDataAttribute()
: base(() => new Fixture().Customize(new AutoMoqCustomization()))
{
}
}
}
[Theory, AutoMoqData]
SomeTestMethod(SomeController c, SomeModel m)
{
var result = c.PostModel(m);
Assert.IsType<OkResult>(result);
}

Related

AutoFixture + NSubstitute + Virtual methods

Wanting to know if there's a way to mock a virtual method on a concrete class using AutoFixture and NSubstitute. I've been able to do this easily with Moq, as can be seen here:
public class SomeConcreteClass
{
public string MethodA()
{
return MethodB();
}
public virtual string MethodB()
{
return "AAA";
}
}
[TestFixture]
public class SomeConcreteClassTests
{
private IFixture _fixture;
private SomeConcreteClass _someConcreteClass;
[SetUp]
protected void Setup()
{
_fixture = new Fixture()
.Customize(new AutoMoqCustomization());
var someConcreteClassMock = _fixture.Create<Mock<SomeConcreteClass>>();
_someConcreteClass = someConcreteClassMock.Object;
someConcreteClassMock.CallBase = true;
}
[Test]
public void SomeScenario()
{
Mock.Get(_someConcreteClass).Setup(m => m.MethodB()).Returns("BBB");
var actual = _someConcreteClass.MethodA();
actual.ShouldBe("BBB");
}
}
This is best achieved if you use AutoFixture's support for Parametrised Tests, here illustrated using xUnit.net (but, IIRC, there's similar support for NUnit):
[Theory, AutoNSubstituteData]
public void ImplicitSubtituteViaAttribute([Substitute]SomeConcreteClass scc)
{
scc.MethodB().Returns("BBB");
var actual = scc.MethodB();
Assert.Equal("BBB", actual);
}
Using the [Substitute] attribute enables you to explicitly tell AutoFixture that, although you asked for a concrete class, it should create it via NSubstitute so that you can override any virtual members it might have.
AutoNSubstituteData is defined like this:
public class AutoNSubstituteDataAttribute : AutoDataAttribute
{
public AutoNSubstituteDataAttribute() :
base(() => new Fixture().Customize(new AutoNSubstituteCustomization()))
{
}
}
AutoDataAttribute comes from AutoFixture.Xunit2, but if you prefer NUnit over xUnit.net, you should be able to use AutoFixture.NUnit3 instead.
Otherwise, I'm not sure you can achieve exactly the same result as with AutoFixture.AutoMoq. In this degenerate example, you can do this:
[Fact]
public void ImperativeWorkaround()
{
var fixture = new Fixture().Customize(new AutoNSubstituteCustomization());
fixture.Register(() => Substitute.For<SomeConcreteClass>());
var scc = fixture.Create<SomeConcreteClass>();
scc.MethodB().Returns("BBB");
var actual = scc.MethodB();
Assert.Equal("BBB", actual);
}
This is, however, fairly pointless, as you could just as well have written this:
[Fact]
public void Reduction()
{
var scc = Substitute.For<SomeConcreteClass>();
scc.MethodB().Returns("BBB");
var actual = scc.MethodB();
Assert.Equal("BBB", actual);
}
In other words, AutoFixture doesn't actually do anything in that workaround.
I could imagine that the real issue is that in real usage, the concrete class in question has other members or constructor data that you wish to fill with data. The problem is that due to the way NSubstitute is designed, I'm not aware of any way you can declaratively ask for a 'substitute'; you'll have to use the Substitute.For method, which then completely short-circuits AutoFixture's ability to hook into the process and add its own behaviour.
With Moq, this is possible because in the OP, you're not asking AutoFixture for a SomeConcreteClass object, but rather for a Mock<SomeConcreteClass>, and that enables AutoFixture to distinguish.
In other words, Moq follows the Zen of Python that explicit is better than implicit, and that makes it extensible to a degree not easily achieved with NSubstitute. For that reason, I've always considered Moq to have the better API.

How to unit test a service call in xUnit and nSubstitute

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.

Unit Testing BLL: mock Repository, UnitOfWork, UnitOfWorkFactory

I need a jump start in testing the methods on my Business layer. Consider the Materials BLL object, how can I test the AddNewMaterial method for it?
interface IGenericRepository<TEntity>
{
TEntity Add(TEntity m);
}
public interface IMaterialRepository : IGenericRepository<Material>
{
}
public interface IUnitOfWork
{
IMaterialRepository Materials { get; private set;}
void Save();
}
public interface IUnitOfWorkFactory
{
IUnitOfWork GetUnitOfWOrk();
}
public class MaterialsBLL
{
private readonly IUnitOfWorkFactory _uowFactory;
//uowFactory comes from DI
public MaterialsBLL(IUnitOfWorkFactory uowFactory)
{
_uowFactory = uowFactory;
}
//TODO: test this
public Material AddNewMaterial(Material m)
{
using(var uow = _uowFactory.GetUnitOfWOrk())
{
var result = uow.Materials.Add(m);
uow.Save();
return result;
}
}
I am using Moq, and XUnit, but am very green. In general I want to do this:
Mock the repositories Add method.
Mock the UoW Materials property to return my repository mock.
Mock the UoWFactory to return the UoW mock.
Create the MaterialsBLL giving the mocked UoWFactory to the contstructor.
Verify that the AddNewMaterials calls the repository's Add, and the UoW's Save, etc.
It seems to me that, I maybe should be creating a Fake MaterialRepository, rather than mocking it? Any other advice? Here is a first crack:
[Fact]
public void TestGetMaterialById()
{
var materialList = GetMaterials();
var materialRepositoryMock = new Mock<IMaterialRepository>();
materialRepositoryMock.Setup(repo => repo.Get(4)).Returns(materialList.First());
var uowMock = new Mock<IUnitOfWork>();
uowMock.SetupProperty<IMaterialRepository>(uow => uow.Materials, materialRepositoryMock.Object);
var uowFactoryMock = new Mock<IUnitOfWorkFactory>();
uowFactoryMock.Setup(f => f.GetUnitOfWork()).Returns(uowMock.Object);
var materialsBll = new Materials(uowFactoryMock.Object);
var result = materialsBll.Get(4);
Assert.Equal(result.MaterialId, 4);
Assert.Equal(result.Name, "Four");
}
When you feel like you need several levels of nested mock objects, there's generally something wrong with your design.
The Law of Demeter warns us here that you should probably not tinker with uow.Materials in MaterialsBLL.
Besides, a Unit of Work is typically not the place to expose Repositories. The code that needs to access Materials will usually have a direct reference to an IMaterialsRepository, not ask it from the UoW, and then the Repository implementation might reference the UoW internally.
This leads to a flatter design and simplifies your production code as well as your tests.

Moq - how to verify method call which parameter has been cleaned (a list)

I've got the following code and I need help to write a unit test for it. I'm using Moq library.
Here's the deal. I have a business class with a dependency to a repository (interface), so I can use it to save my entities to the database. My entity is basically a list of strings. The method AddAndSave, from MyBusinessClass, grab the value it receives as a parameters, put it into the list and call Save method from IRepository. Then, I clear the list of my entity. The code below show this example (I've made it simple so I can explain it here).
There's a unit test, too.
using System.Collections.Generic;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
namespace TestesGerais
{
public class MyEntity
{
public MyEntity()
{
MyList = new List<string>();
}
public List<string> MyList { get; set; }
}
public interface IRepository
{
void Save(MyEntity entity);
}
public class MyBusinessClass
{
public IRepository Repository { get; set; }
private MyEntity _entity = new MyEntity();
public void AddAndSave(string info)
{
_entity.MyList.Add(info);
Repository.Save(_entity);
_entity.MyList.Clear(); // for some reason I need to clear it
}
}
[TestClass]
public class UnitTest10
{
[TestMethod]
public void TestMethod1()
{
var mock = new Mock<IRepository>();
MyBusinessClass b = new MyBusinessClass() { Repository = mock.Object };
b.AddAndSave("xpto");
mock.Verify(m => m.Save(It.Is<MyEntity>(x => x.MyList[0] == "xpto")), Times.Exactly(1));
}
}
}
My unit-test check if the IRepository's Save method was called with its parameter (an entity) having one element in the list, and having the value "xpto" in this element.
When I run this test, it turns red with the error message "Test method TestesGerais.UnitTest10.TestMethod1 threw exception:
System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index".
Ok, this is caused by the list that has been cleaned. If I comment the line "_entity.MyList.Clear();", everything goes well.
My question is: how can I test this without commenting the "Clear" line in my business class, and making sure that my repository's method is called passing the specific value (entity with one element with value "xpto")?
Thanks
I've changed my unit test using the Callback feature of Moq. This way, I can setup the mock so when AddAndSave is called, the parameter it receives is saved into a variable from my unit test, and I can assert it later.
[TestMethod]
public void TestMethod1()
{
var mock = new Mock<IRepository>();
string result = string.Empty;
mock.Setup(m => m.Save(It.IsAny<MyEntity>())).Callback((MyEntity e) => { result = e.MyList[0]; });
MyBusinessClass b = new MyBusinessClass() { Repository = mock.Object };
b.AddAndSave("xpto");
Assert.AreEqual(result, "xpto");
}
You could split your method up a bit. "AddAndSave" isn't all it does. You could then just test the behaviour of the adding and saving bit in isolation.

How do you test an extension method on an Interface which calls another method in that Interface with a mock created by Rhino Mocks?

I'm testing an extension method on an interface 'ISomeInterface'. The extension method actually calls to another method in the interface.
How do I set up a mock and the appropriate expectations (i want to set the expectation that 'SomeMethod', which is an defined method in the interface with a different signature then this extension method, will be called with 'someDifferentParam')
// Extension Method
public static ISomeInterface SomeMethod(this ISomeInterface someInterface, string someParam)
{
// do work, then call the defined method in the interface
someInterface.SomeMethod(int someDifferentParam)
return someInterface;
}
// tried to do the following but it errors
[Test]
public void SomeMethod_WithSomeInterface_CallsOtherSomeMethod()
{
const string someParam = "something";
const int someOtherParam = 1;
var mock = MockRepository.GenerateMock<ISomeInterface>();
mock.SomeMethod(someParam);
mock.AssertWasCalled(x => x.SomeMethod(someOtherParam));
}
EDIT
I finally got it working, but I'm open to suggestions/criticism. I'm just learning the ins/outs of Rhino Mocks myself =)
here is the real thing that I was testing. Since you can't compare two NHibernate.Criterion.Order objects by doing an Is.Equal or Is.SameAs I had to capture the arguments passed to the method call and then Assert on the ToString of the Order object because there are no public properties exposed on it.
// Extension Method
public static class NHibernateExtensions
{
public static ICriteria AddOrder(this ICriteria criteria, params OrderBy[] orderBys)
{
foreach (var b in orderBys)
{
var arr = b.Property.Split(',');
for (var i = 0; i < arr.Length; i++)
{
criteria.AddOrder(b.Direction == OrderDirection.Ascending
? Order.Asc(arr[i])
: Order.Desc(arr[i]));
}
}
return criteria;
}
}
// here is the test that works
[TestFixture]
public class NHibernateExtensionsTester : TestBase
{
[Test]
public void AddOrder_1OrderBy_CallsAddOrderOnICriteriaWithCorrectOrder()
{
const string testProperty = "SomeProperty";
var expected = (Order.Asc(testProperty)).ToString();
var orderBys = new[]
{
new OrderBy
{
Direction = OrderDirection.Ascending,
Property = testProperty
}
};
var mockCriteria = M<ICriteria>();
mockCriteria.AddOrder(orderBys);
var orderArgument = (Order)((mockCriteria.GetArgumentsForCallsMadeOn(x => x.AddOrder(null)))[0][0]);
Assert.That(orderArgument.ToString(), Is.EqualTo(expected));
}
}
Jon, since in effect you're just testing your extension method I see nothing wrong and this. I tried your code out and worked fine for me. Here is the exact code that I ran (using xunit.net and TD.Net). The test passed.
What error are you getting?