I need to mock a DbSet with RhinoMock. I found a way to mock IDbSet, but not DbSet. I found a way with another mocking framework, but i have to use RhinoMock. Can somebody please translate it to rhino mock?
I found this on http://www.loganfranken.com/blog/517/mocking-dbset-queries-in-ef6/:
private static DbSet<T> GetQueryableMockDbSet<T>(params T[] sourceList) where T : class
{
var queryable = sourceList.AsQueryable();
var dbSet = new Mock<DbSet<T>>();
dbSet.As<IQueryable<T>>().Setup(m => m.Provider).Returns(queryable.Provider);
dbSet.As<IQueryable<T>>().Setup(m => m.Expression).Returns(queryable.Expression);
dbSet.As<IQueryable<T>>().Setup(m => m.ElementType).Returns(queryable.ElementType);
dbSet.As<IQueryable<T>>().Setup(m => m.GetEnumerator()).Returns(() => queryable.GetEnumerator());
return dbSet.Object;
}
Thanks
Update
While RhinoMocks supports mocking multiple interfaces with the same mock, as I utilized in my initial answer, it apparently doesn't support explicit intefaces, which DbSet utilizes for IQueryable. As #Dosihris pointed out in the comment, it throws an exception saying
Due to how CLR handles explicit interface implementation, we're not able to proxy this method.
This appears to be an exception from the version of Castle.DynamicProxy (v2.1.0.5967) embedded in RhinoMocks, which is from pre-2010. Newer versions of DynamicProxy support this, so if you really wanted to be adventurous, you could recompile RhinoMocks with an updated version of DynamicProxy.
Or, you could try referencing DynamicProxy directly in your test project and using binding redirects to force RhinoMocks to use the newer version. Given the age of the version in RhinoMocks, there's likely incompatibilities with the newer DynamicProxy APIs, so this is likely not going to be successful.
Or, you could move to a framework that is still actively maintained, such as Moq or NSubstitute (which both use newer versions of DynamicProxy).
This is the equivalent logic using RhinoMocks:
using Rhino.Mocks;
private static DbSet<T> GetQueryableMockDbSet<T>(params T[] sourceList) where T : class
{
var queryable = sourceList.AsQueryable();
var dbSet = Rhino.Mocks.MockRepository.GenerateMock<DbSet<T>, IQueryable<T>>();
((IQueryable<T>)dbSet).Expect(m => m.Provider).Return(queryable.Provider);
((IQueryable<T>)dbSet).Expect(m => m.Expression).Return(queryable.Expression);
((IQueryable<T>)dbSet).Expect(m => m.ElementType).Return(queryable.ElementType);
((IQueryable<T>)dbSet).Expect(m => m.GetEnumerator())
.Return(null) // will be ignored but still the API requires it
.WhenCalled((methodInvokation) => methodInvokation.ReturnValue = queryable.GetEnumerator());
return dbSet;
}
Depending on whether you want to do verification that the properties were called or not, you may want to use .Stub() instead of .Expect() in each of the above.
Related
I've got a class that I'm trying to unit test but it uses a DaprClient object (from the SDK), which doesn't work in my unit test envioronment.
I would like to create a mock and use that instead but the only interface DaprClient implements is IDisposable.
Is there a way to mock DaprClient for unit tests?
The only solution I can think of would be to wrap DaprClient in a class with an interface and use this wrapper everywhere. This just feels really messy and will need the wrapper to be updated every time I want to use a new method on the DaprClient.
I'm open to other solutions which might bypass the problem but I'd prefer a simple replace with mock type approach.
I'm using .Net 5, xUnit and Moq in Visual Studio 2019 on Windows (although some team members use Macs so it needs to work on both platforms).
In this particular instance, I'm using the DaprClient.GetBulkSecretAsync method but I'd like a solution that I can use elsewhere, if possible.
You need to use one of two options
a mocking framework that uses shims as they make a mock object based on a concrete class. Fakes from visual studio enterprise and other paid frameworks have it. Fewer opensource frameworks have the option. Pose is one with the option perhaps via Shimmy
wrap the class in a class that uses a interface you can use for mocking (the worst possibility)
using Dapr.Client;
using FluentAssertions;
using Moq;
[TestMethod("How to mock GetBulkSecretAsync - 68362431")]
public async Task TestMethod1()
{
//arrange
var daprClient = new Mock<DaprClient>();
var exampleService = new ExampleService(daprClient.Object);
daprClient.Setup(d => d.GetBulkSecretAsync("my-store",
It.IsAny<IReadOnlyDictionary<string, string>>(),
It.IsAny<CancellationToken>()))
.ReturnsAsync(new Dictionary<string, Dictionary<string, string>>
{
{
"example",
new Dictionary<string, string>
{
{ "i don't understand the builk API (yet)", "some value" }
}
}
});
//act
var actual = await exampleService.GetBulkSecrets("my-store");
//assert
actual.Should().BeEquivalentTo(new Dictionary<string, Dictionary<string, string>>
{
{
"example",
new Dictionary<string, string>
{
{ "i don't understand the builk API (yet)", "some value" }
}
}
});
}
references:
full project
Accessing Dapr secrets building block using Dapr .NET SDK
but I'd like a solution that I can use elsewhere, if possible
In general, we need to use the abstract methods defined in the DarpClient.
I'm working on a dotnet core project, trying to mock some third party classes in my Xunit.net tests. The class I'm trying to fake is not mockable through constrained frameworks like Moq or NSubstitute. So I need an unconstrained framework to do that.
Say I want to fake DateTime.Now in my .net core test projects.
In .net 4.5 we have MSFakes(Moles), Smocks, etc. None of them support dotnet core framework yet. Shim is not ported to dotnet core yet.
Anyone knows any isolation framework or technique that will achieve my goal for .NET Core at the present time?
You could try a different way: wrap those third party libs with your own interfaces and wrapper classes. Then use a dummy object implementing that interface.
Things become more complicated with static properties like DateTime.Now. But it works similar: define an ITimeProvider interface with a Now property. Add a DateTimeWrapper : ITimeProvider with a public DateTime Now => DateTime.Now;, and - for convenience, but not required - a static class around it, e.g.
static class MyClock
{
static ITimeProvider _Instance;
static void SetInstanceForTesting(ITimeProvider instance)
{ _Instance = instance; }
static DateTime Now => _Instance.Now;
}
Alternatively, you may inject an ITimeProvider instance to the objects needing it.
A somewhat late reply, but for anyone else looking after the same kind of functionality I would recommend the open source git project prig: https://github.com/urasandesu/Prig It can fake static methods (they even have an example of faking and isolating DateTime.Now) and is an alternative to Microsoft Fakes, TypeMock and JustMock (all who cost money or require ultimate editions of visual studio to use).
Pose is an option. It's free full in memory
Https://GitHub.com/tonerdo/pose
I'm in the process of learning Node.js and am wondering about how people mock dependencies in their modules when unit testing.
For example:
I have a module that abstracts my MongoDB calls. A module that uses this module may start out something like this.
var myMongo = require("MyMongoModule");
// insert rest of the module here.
I want to ensure I test such a module in isolation while also ensuring that my tests don't insert records/documents into Mongo.
Is there a module/package that I can use that proxies require() so I can inject in my own mocks? How do other's typically address this issue?
You can use a dependency injection library like nCore
To be honest, the hard part of this is actually mocking out the mongoDB API, which is complex and non trivial. I estimate it would take about a week to mock out most of the mongo API I use so I just test againts the a local mongodb database on my machine (which is always in a weird state)
Then with nCore specific syntax
// myModule.js
module.exports = {
myMethod: function () {
this.mongo.doStuff(...)
},
expose: ["myMethod"]
};
// test-myModule.js
var module = require("myModule")
module.mongo = mongoMock
assert(module.myMethod() === ...)
After reviewing Ryanos's suggestion as well as the Horaa package on npm, I discovered this thread on the Google Group that pointed me towards Sandboxed-Module.
Sandboxed-Module allows me to inject/override require() without me having to expose such dependencies for my unit tests.
I'm still up for other suggestions; however, Sandboxed-Module appears to fit my needs at the moment.
You easily mock require by using "a": https://npmjs.org/package/a
e.g. need to mock require('./foo') in unit test:
var fakeFoo = {};
var expectRequire = require('a').expectRequire;
expectRequire('./foo).return(fakeFoo);
//in sut:
var foo = require('./foo); //returns fakeFoo
Overwriting require to inject your mocks is a possible solution. However, I concur in Raynos' opinion:
I personally find the methodology of overwriting require on a file by file basis an "ugly hack" and prefer to go for proper DI. It is however optimum for mocking one or two modules on an existing code base without rewriting code for DI support.
To use proper dependency injection not only saves you an "ugly hack" but also allows you to apply additional use cases apart from injecting mocks. In production you may e.g. usually instantiate connections over http and in certain circumstances inject a different implementation to establish a connection over VPN.
If you want to look for a dependency injection container read this excellent article and check out Fire Up! which I implemented.
Short version of my questions:
Can anyone point me toward some good, detailed sources from which I
can learn how to implement testing in my MVC 3 application, using
NUnit, Ninject 2, and Moq?
Can anyone here help clarify for me how Controller-Repository
decoupling, mocking, and dependency injection work together?
Longer version of my questions:
What I'm trying to do ...
I am currently beginning to create an MVC 3 application, which will use Entity Framework 4, with a database first approach. I want to do this right, so I am trying to design the classes, layers, etc., to be highly testable. But, I have little to no experience with unit testing or integration testing, other than an academic understanding of them.
After lots of research, I've settle on using
NUnit as my testing framework
Ninject 2 as my dependency injection framework
Moq as my mocking framework.
I know the topic of which framework is best, etc., could enter into this, but at this point I really don't know enough about any of it to form a solid opinion. So, I just decided to go with these free solutions which seem to be well liked and well maintained.
What I've learned so far ...
I've spent some time working through some of this stuff, reading resources such as:
Implementing the Repository and Unit of Work Patterns in an
ASP.NET MVC Application
Building Testable ASP.NET MVC Applications
NerdDinner Step 12: Unit Testing
Using Repository and Unit of Work patterns with Entity Framework
4.0
From these resources, I've managed to workout the need for a Repository pattern, complete with repository interfaces, in order to decouple my controllers and my data access logic. I have written some of that into my application already, but I admit I am not clear as to the mechanics of the whole thing, and whether I am doing this decoupling in support of mocking, or dependency injection, or both. As such, I certainly wouldn't mind hearing from you guys about this too. Any clarity I can gain on this stuff will help me at this point.
Where things got muddy for me ...
I thought I was grasping this stuff pretty well until I started trying to wrap my head around Ninject, as described in Building Testable ASP.NET MVC Applications, cited above. Specifically, I got completely lost around the point in which the author begins describing the implementation of a Service layer, about half way into the document.
Anyway, I am now looking for more resources to study, in order to try to get various perspectives around this stuff until it begins to make sense to me.
Summarizing all of this, boiling it down to specific questions, I am wondering the following:
Can anyone point me toward some good, detailed sources from which I
can learn how to implement testing in my MVC 3 application, using
NUnit, Ninject 2, and Moq?
Can anyone here help clarify for me how Controller-Repository
decoupling, mocking, and dependency injection work together?
EDIT:
I just discovered the Ninject official wiki on Github, so I'm going to start working through that to see if it starts clarifying things for me. But, I'm still very interested in the SO community thoughts on all of this :)
If you are using the Ninject.MVC3 nuget package, then some of the article you linked that was causing confusion will not be required. That package has everything you need to start injecting your controllers which is probably the biggest pain point.
Upon installing that package, it will create a NinjectMVC3.cs file in the App_Start folder, inside that class is a RegisterServices method. This is where you should create the bindings between your interfaces and your implementations
private static void RegisterServices(IKernel kernel)
{
kernel.Bind<IRepository>().To<MyRepositoryImpl>();
kernel.Bind<IWebData>().To<MyWebDAtaImpl>();
}
Now in your controller you can use constructor injection.
public class HomeController : Controller {
private readonly IRepository _Repo;
private readonly IWebData _WebData;
public HomeController(IRepository repo, IWebData webData) {
_Repo = repo;
_WebData = webData;
}
}
If you are after very high test coverage, then basically anytime one logical piece of code (say controller) needs to talk to another (say database) you should create an interface and implementation, add the definition binding to RegisterService and add a new constructor argument.
This applies not only to Controller, but any class, so in the example above if your repository implementation needed an instance of WebData for something, you would add the readonly field and the constructor to your repository implementation.
Then when it comes to testing, what you want to do is provide mocked version of all required interfaces, so that the only thing you are testing is the code in the method you are writing the test for. So in my example, say that IRepository has a
bool TryCreateUser(string username);
Which is called by a controller method
public ActionResult CreateUser(string username) {
if (_Repo.TryCreateUser(username))
return RedirectToAction("CreatedUser");
else
return RedirectToAction("Error");
}
What you are really trying to test here is that if statement and the return types, you do not want to have to create a real repository that will return true or false based on special values you give it. This is where you want to mock.
public void TestCreateUserSucceeds() {
var repo = new Mock<IRepository>();
repo.Setup(d=> d.TryCreateUser(It.IsAny<string>())).Returns(true);
var controller = new HomeController(repo);
var result = controller.CreateUser("test");
Assert.IsNotNull(result);
Assert.IsOfType<RedirectToActionResult>(result)
Assert.AreEqual("CreatedUser", ((RedirectToActionResult)result).RouteData["Action"]);
}
^ That won't compile for you as I know xUnit better, and do not remember the property names on RedirectToActionResult from the top of my head.
So to sum up, if you want one piece of code to talk to another, whack an interface in between. This then allows you to mock the second piece of code so that when you test the first you can control the output and be sure you are testing only the code in question.
I think it was this point that really made the penny drop for me with all this, you do this not necessarily becase the code demands it, but because the testing demands it.
One last piece of advice specific to MVC, any time you need to access the basic web objects, HttpContext, HttpRequest etc, wrap all these behind an interface as well (like the IWebData in my example) because while you can mock these using the *Base classes, it becomes painful very quickly as they have a lot of internal dependencies you also need to mock.
Also with Moq, set the MockBehaviour to Strict when creating mocks and it will tell you if anything is being called that you have not provided a mock for.
Here is the application that I'm creating. It is open source and available on github, and utilizes all of the required stuff - MVC3, NUnit, Moq, Ninject - https://github.com/alexanderbeletsky/trackyt.net/tree/master/src
Contoller-Repository decoupling is simple. All data operations are moved toward the Repository. Repository is an implementation of some IRepository type. The controller never creates repositories inside itself (with the new operator) but rather receives them either by constructor argument or property.
.
public class HomeController {
public HomeController (IUserRepository users) {
}
}
This technique is called "Inversion of Control." To support inversion of control you have to provide some "Dependency Injection" framework. Ninject is a good one. Inside Ninject you associate some particular interface with an implementation class:
Bind<IUserRepository>().To<UserRepository>();
You also substitute the default controller factory with your custom one. Inside the custom one you delegate the call to the Ninject kernel:
public class TrackyControllerFactory : DefaultControllerFactory
{
private IKernel _kernel = new StandardKernel(new TrackyServices());
protected override IController GetControllerInstance(
System.Web.Routing.RequestContext requestContext,
Type controllerType)
{
if (controllerType == null)
{
return null;
}
return _kernel.Get(controllerType) as IController;
}
}
When the MVC infrastructure is about to create a new controller, the call is delegated to the custom controller factory GetControllerInstance method, which delegates it to Ninject. Ninject sees that to create that controller the constructor has one argument of type IUserRepository. By using the declared binding, it sees that "I need to create a UserRepository to satisfy the IUserRepository need." It creates the instance and passes it to the constructor.
The constructor is never aware of what exact instance would be passed inside. It all depends on the binding you provide for that.
Code examples:
https://github.com/alexanderbeletsky/trackyt.net/blob/master/src/Web/Infrastructure/TrackyServices.cs https://github.com/alexanderbeletsky/trackyt.net/blob/master/src/Web/Infrastructure/TrackyControllerFactory.cs https://github.com/alexanderbeletsky/trackyt.net/blob/master/src/Web/Controllers/LoginController.cs
Check it out : DDD Melbourne video - New development workflow
The whole ASP.NET MVC 3 development process was very well presented.
The third party tools I like most are:
Using NuGet to install Ninject to enable DI throughout the MVC3
framework
Using NuGet to install nSubstite to create mocks to enable unit
testing
I've created a unit test that tests interactions on my ViewModel class in a Silverlight application. To be able to do this test, I'm mocking the service interface, injected to the ViewModel. I'm using Moq framework to do the mocking.
to be able to verify bounded object in the ViewModel is converted properly, I've used a callback:
[Test]
public void SaveProposal_Will_Map_Proposal_To_WebService_Parameter()
{
var vm = CreateNewCampaignViewModel();
var proposal = CreateNewProposal(1, "New Proposal");
Services.Setup(x => x.SaveProposalAsync(It.IsAny<saveProposalParam>())).Callback((saveProposalParam p) =>
{
Assert.That(p.plainProposal, Is.Not.Null);
Assert.That(p.plainProposal.POrderItem.orderItemId, Is.EqualTo(1));
Assert.That(p.plainProposal.POrderItem.orderName, Is.EqualTo("New Proposal"));
});
proposal.State = ObjectStates.Added;
vm.CurrentProposal = proposal;
vm.Save();
}
It is working fine, but if you've noticed, using this mechanism the Assert and Act part of the unit test have switched their parts (Assert comes before Acting). Is there a better way to do this, while preserving correct AAA order?
I'm not sure that you've changed the semantics of the AAA order. Consider the execution of the test. Your mocked interface will not be called until the Action invokes it. Therefore, during execution, your program still follows the Arrange, Act, and Assert flow.
The alternative would be to use Data Injection and create an interface between your CampaignViewModel and the web service that it uses. You can then create a class in your UnitTests that saves your parameter information and Assert on that class member/property rather than use Moq to create a proxy on the fly.
Moq should not be used to simulate storage or assignment. Rather, use Moq to provide dummy mechanisms and values to allow your Unit Tests to execute. If Asserting storage is a requirement, then take the time to create a class that will hold on to your values.