I have a sample code (pasted below). I am using Xunit, NSubstitute and NCrunch. When I run the test in Visual Studio's Test Explorer, the test passes. When I debug, the test runs correctly. With NCrunch, I am facing a bizzare behavior, the test passes, and then fails, then it passes and then fails, and it continues like that.
[Fact]
public void Test()
{
var drink = Substitute.For<IDrink>();
var greetings = new Greetings();
var derived = new Derived();
derived.Test(drink, greetings);
}
public class Greetings
{
public string Message { get; set; }
}
public interface IDrink
{
void Prepare(Greetings greetings);
}
public abstract class Base
{
public abstract void Test(IDrink drink, Greetings greetings);
}
public class Derived : Base
{
public override void Test(IDrink drink, Greetings greetings)
{
drink.Prepare(greetings); /////////// The error is here
}
}
public class NullDerived : Derived
{
public override void Test(IDrink drink, Greetings greetings)
{
throw new Exception("No value found");
}
}
The error NCrunch throwing is:
NSubstitute.Exceptions.RedundantArgumentMatcherException: Some argument specifications (e.g. Arg.Is, Arg.Any) were left over after the last call.
This is often caused by using an argument spec with a call to a member NSubstitute does not handle (such as a non-virtual member or a call to an instance which is not a substitute), or for a purpose other than specifying a call (such as using an arg spec as a return value). For example:....
I have tried to remove the parameter from Prepare(Greetings greetings) method, then NCrunch passes the test every single time.
As the error is suggesting, I am not passing the paramaters from the Test correctly.
My question is: What is the correct way of passing the greetings object to Prepare method. I have tried Arg.Any but it didn't work.
Any help is appreciated.
Edit 1:
I am seeing the same behvarior using Reshaper's Unit Test Coverage.
Related
I will try to show my problem with a sample code easier to understand.
I have used WebApplicationFactory to develop my acceptance tests. Let's say that I have the typical minimal Program.cs with the following line to register one of my modules:
builder.Services.RegisterModule<StartupRegistrationModule>(builder.Configuration, builder.Environment);
And this module is declared like this:
internal sealed class StartupRegistrationModule : IServiceRegistrationModule
{
public static Dictionary<string, string> _dictionary = new();
public void Register(IServiceCollection services, IConfiguration configuration, IHostEnvironment hostEnvironment)
{
// Lot of modules being registered
_dictionary.Add("key", "value");
}
}
One of my tests file is like this:
public sealed class MyTests : AcceptanceTestBase
{
[Fact]
public void Test1()
{
// arrange
// act
// assert
}
[Fact]
public void Test2()
{
// arrange
// act
// assert
}
[Fact]
public void Test3()
{
// arrange
// act
// assert
}
}
And AcceptanceTestBase is:
public abstract class AcceptanceTestBase : IDisposable
{
protected HttpClient _httpClient;
protected WebApplicationFactory<Program> _webApplicationFactory;
public AcceptanceTestBase()
{
_webApplicationFactory = new WebApplicationFactory<Program>()
.WithWebHostBuilder(builder =>
{
// ... Configure test services
});
_httpClient = _webApplicationFactory.CreateClient();
}
public void Dispose()
{
_httpClient.Dispose();
_webApplicationFactory.Dispose();
}
}
If I try to execute all these tests my tests will fail in the second test run because the WebApplicationFactory is trying to build again the Application but it already has the key in the dictionary and it will fail. See the image for more understanding on the problem.
So my question is, how can I build the application in different scopes to do not share this dictionary state?
Thanks :)
Update:
The real static dictionary is saved behind this nuget package that keeps the track of all my circuit breaker policies state. I do not actually need even the HttpClients for my tests but did not find a way to remove them and not load this. I tried removing all the HttpClients to see if it also removes their dependencies, but it does not seem to make the trick.
It is because you are using:
internal sealed class StartupRegistrationModule : IServiceRegistrationModule
{
/// .. static here
public static Dictionary<string, string> _dictionary = new();
public void Register(IServiceCollection services, IConfiguration configuration, IHostEnvironment hostEnvironment)
{
// Lot of modules being registered
_dictionary.Add("key", "value");
}
}
The static Dictionary is shared over all your tests because they run in the same process.
Each test starts a new (Test-)WebHost but the dictionary remains untouched.
My proposal is to not use statics anywhere in DI context to prevent such hidden traps.
I don't know the purpose of your Dictionary here but maybe you can extract this to a singleton registration which you can replace in your (Test.)WebHost on each new test / startup?
Here's the code. The code in method test and test2 are different because the parameter passed to Test constructor are different. Actually, if I change any parameter to null, intellij stops reporting the duplication. Is there any way to fix this?
---- Updated --------
I pass 2 functions doing totally different things but intellij still reports duplication
public class TestMain {
public void test(int a)
{
System.out.println("haha");
System.out.println("hahaa");
TestMain testMain = new TestMain();
new Test(testMain::test3);
System.out.println("hahaaa");
}
public void test2(int a)
{
System.out.println("haha");
System.out.println("hahaa");
TestMain testMain = new TestMain();
new Test(testMain::still_dup);
System.out.println("hahaaa");
}
public void test3(int a) {
System.out.println("abc");
}
public void still_dup(int a) {
String b = "edf";
b.toLowerCase();
}
public class Test {
Test(handler h) {
}
}
public interface handler<M> {
void entitySelector(int a);
}
public static void main(String[] args) {
TestMain test = new TestMain();
test.test(1);
System.out.println("-------");
test.test2(2);
}
}
I think the best way to fix this is to replace test and test2 by a single method. You don't have to distinguish what to pass the constructor because it's the current method. This might be the reason why code duplication is reported. The methods can be replaced by a single one without problems.
I have issue while trying to mock method that returns instance of abstract class with Rhino Mocks. Issue is that MammalBase constructor is invoked while stub is created and I would like to avoid that. All source code in question is locked for editing and only tests can be changed.
Eventually, base class is processing something by type attributes in constructor, and throws exception if no adequate attributes are detected. That causes a extensive logging.
My hope is to remove unnecessary logs from tests.
Is it possible to instruct Rhino Mocks not to instantiate return type (MammalBase) when it creates proxy while creating a stub?
Is explicit attribute or type setting possible for return value while Rhino creates stub for method with abstract class instance as return type?
Is avoiding constructor even possible without making stubbed method return interface?
I found that issue does not exist if:
1. Stubbed method returns array like MammalBase[],
2. Stubbed method returns derivate class like "Human" first, since no more constructors of base class are invoked.
Thanks in advance!
(Code sample)
public interface IDetermineMammalByType
{
MammalBase DetermineMammalByType(MammalBase creature);
}
public abstract class MammalBase
{
protected MammalBase()
{
CustomAttribute[] attributes = (CustomAttribute[])Attribute.GetCustomAttributes(this.GetType(), typeof(CustomAttribute));
if (!attributes.Any(x=> x as CustomAttribute != null))
{
//This causes issue
throw new Exception();
}
}
}
[CustomAttribute()]
public class Human : MammalBase { }
[System.AttributeUsage(System.AttributeTargets.Class |
System.AttributeTargets.Struct)]
public class CustomAttribute : System.Attribute
{
public CustomAttribute() { }
}
public class MammalDetector : IDetermineMammalByType
{
public MammalBase DetermineMammalByType(MammalBase creature)
{
//Some logic
return null;
}
}
//TEST
[TestMethod()]
public void DetermineMammalByTypeTest()
{
IDetermineMammalByType myTest = MockRepository.GenerateStub<IDetermineMammalByType>();
var creature = new Human();
//Here it fails while mocking method
myTest.Stub(x => x.DetermineMammalByType(creature)).Return(new Human());
}
Look at this very simple example: Calling CreateCar it works, calling GetCar it fails, saying "Error activating ICar: No matching bindings are available, and the type is not self-bindable".
public interface ICar { }
public class Car : ICar
{
public Car(string carType) { }
}
public interface ICarFactory
{
ICar CreateCar(string carType); // this is fine
ICar GetCar(string carType); // this is bad
}
public class CarModule : NinjectModule
{
public override void Load()
{
Bind<ICarFactory>().ToFactory();
Bind<ICar>().To<Car>();
}
}
public class Program
{
public static void Main()
{
using (var kernel = new StandardKernel(new FuncModule(), new CarModule()))
{
var factory = kernel.Get<ICarFactory>();
var car1 = factory.CreateCar("a type");
var car2 = factory.GetCar("another type");
}
}
}
Is assume it must be related to some kind of convention with Get*ClassName* (something like the NamedLikeFactoryMethod stuff). Is there any way to avoid this convention to be applied? I don't need it and I don't want it (I already wasted too much time trying to figure out why the binding was failing, it was just luck that I made a typo in 1 of my 10 factories and I noticed it to work just because the factory method name was "Ger" instead of "Get").
Thanks!
Yes, there is a convention, where the Get is used to obtain instances using a named binding. The factory extension generates code for you so you don't have to create boilerplate code for factories. You don't need to use it, if you don't want to.
But if you do, you are bound to its conventions. Use Create to build instances and Get to retrieve instances via a named binding.
All this is documented in the wiki.
As far as I see, unless my mvc4 app uses windows authentication (and so my controllers tries to read the User objects) when I create my controller instance from a TestMethod, the User object remains null. So my tests fails. What can I do to get them work?
Additional informations:
This is my test:
[TestMethod]
public void Create()
{
var ctrl = new LanguageController();
var res = ctrl.Manage() as ViewResult;
Assert.IsNotNull(res);
Assert.AreEqual(res.ViewName, "Create");
}
And my LanguageController has a base class:
public class LanguageController : MyController
{
Which has a constructor, inside it I try to discover the user rights by an external Right Manager.
public class MyController : Controller
{
protected Rights rm;
public MyController()
{
this.rm = RightManager.Discover(User.Identity);
}
Here in this constructor I see the User is null.
Okay, there are few issues with your Unit test and I will go through them as I explain why the User is null.
It is simply because you haven't provide a stubbed version of the User (IPrincipal) instance. So you need to find a way to inject that into your Controller. It is important you externalize as much dependencies in your Controller so it provides not a clean Controller to work with but also and importantly promote the testability.
What I would do inject the dependencies as below.
Your SUT (System Under Test)
public class MyController : Controller
{
protected Rights rm;
public MyController(IPrincipal user, IRightManager rightManager)
{
this.rm = rightManager.Discover(user.Identity);
}
}
public class LanguageController : MyController
{
public LanguageController(IPrincipal user, IRightManager rightManager)
: base(user, rightManager)
{
}
public ActionResult Manage()
{
return View("Manage");
}
}
This gives me the ability to inject a fake User and also a fake Right Manager.
So how would you get the real User, RightManager when you run the application at runtime?
You can inject the dependencies to the Controller during the Controller creation.
If you don't use a dependency injection framework (Ideally you should), you can still inject dependencies in a manual way. For example, creating property in your Controller and inject the real instance in the Controller, and during the Unit Testing time inject the fake instance etc. I won't go into detail as I'm deviating a bit - but you can find lot SO questions/web references in regards to this aspect.
Your Unit test
Now you have a way to inject your dependencies you can easily inject them from your Unit test. You can either using an Isolation framework (AKA and Mock object framework) or you can inject them as the old school way - which is the Hand written mocks/fakes/stubs. I suggest using an Isolation framework. Creating manual fakes, introduces unnecessary code duplication and maintenance issue. Since I don't know which framework you prefer, I created few handwritten fakes/mocks/stubs.
public class FakeRightManager : IRightManager {
public Rights Discover(IIdentity identity) {
return new Rights();
}
}
public class MyFakeIdentity : IIdentity {
public string AuthenticationType {
get { throw new NotImplementedException(); }
}
public bool IsAuthenticated {
get { throw new NotImplementedException(); }
}
public string Name {
get { throw new NotImplementedException(); }
}
}
public class MyFakePrincipal : IPrincipal {
public IIdentity Identity {
get { return new MyFakeIdentity(); }
}
public bool IsInRole(string role) {
throw new NotImplementedException();
}
}
You Unit Test :
[TestMethod]
public void ManageAction_Execute_ReturnsViewNameManager()
{
var fakeUser = new MyFakePrincipal();
var fakeRightManager = new FakeRightManager();
var ctrl = new LanguageController(fakeUser, fakeRightManager);
var res = ctrl.Manage() as ViewResult;
Assert.AreEqual<string>(res.ViewName, "Manage");
}
In your test you check for Assert.IsNotNull(res); this not necessary as if the res is null your second assert going to fail anyway.
Also always give a very descriptive precise Unit Test name. Reflect what you exactly testing. It improves the test readability and maintainability.