I have a complex object that I'm trying to fake.
interface IContext
{
User User { get; }
}
A.CallTo(
() => _fakeContext.User.Subscription.Attributes)
.Returns(new List<Attribute>());
But I get the next exception:
The current proxy generator can not intercept the specified method for the following reasons: - Non virtual methods can not be intercepted
All nested types are properties, and they are simple anemic types with get; set; property modifiers. And when I look into the debugger they all are fakes.
Is there any way to setup the last property of the chain and avoid setuping all previous ones?
If your objects are anemic enough, you might want to give AutoFixture a go:
var fake = A.Fake<>();
var fixture = new Fixture();
// If it's possible [1], AutoFixture will generate entire object graph
var user = fixture.CreateAnonymous<User>();
// Since data will be random [2], you can overwrite properties as you like
user.User.Subscription.Attributes = new List<Attributes>();
A.CallTo(() => fake.User).Returns(user);
In order for it to work, your custom objects need to have public constructor and preferably avoid using interfaces (but that can be mitigated with auto-mocking extensions, like AutoFakeItEasy).
The .Build method provides fluent API to customize objects autogeneration, so the randomness can be controlled
Related
So I've build a WebAPI from scratch, including some best practices that I've found online such as Dependency Injection and Domain<->DTO mapping using auto mapper etc.
My API Controllers now look similar to this
public MyController(IMapper mapper)
{
}
and AutoMapper Registry:
public AutoMapperRegistry()
{
var profiles = from t in typeof(AutoMapperRegistry).Assembly.GetTypes()
where typeof(Profile).IsAssignableFrom(t)
select (Profile)Activator.CreateInstance(t);
var config = new MapperConfiguration(cfg =>
{
foreach (var profile in profiles)
{
cfg.AddProfile(profile);
}
});
For<MapperConfiguration>().Use(config);
For<IMapper>().Use(ctx => ctx.GetInstance<MapperConfiguration>().CreateMapper(ctx.GetInstance));
}
I'm also building a few test cases, implementing MOQ, and this is where i feel a little unsure. whenever calling my controllers, I need to pass in an IMapper like this:
var mockMapper = new Mock<IMapper>();
var controller = new MyController(mockMapper.Object);
But then, how do i configure the IMapper to have the correct mappings? It feels redundant to recreate the same logic I've already created before to configure the Mapper. so I am wondering what is the recommended approach to do this?
That's pretty simple: if you mock IMapper and imagine it as a fully abstract concept of mapping data from one object to another, then you have to treat is an abstraction and not imply there's a real automapper behind it.
First you should not register any existing profile at all, you should instead setup IMapper.Map method to return specific object when given another object.
So for each profile used for specific method you have to do a setup, looking approximately like this:
var mockMapper = new Mock<IMapper>();
mockMapper.Setup(x => x.Map<DestinationClass>(It.IsAny<SourceClass>()))
.Returns((SourceClass source) =>
{
// abstract mapping function code here, return instance of DestinationClass
});
In this case, your test knows nothing about actual IMapper implementation - it just uses it methods to get the data you expect from actual IMapper implementation to receive.
This might me another solution
//auto mapper configuration
var mockMapper = new MapperConfiguration(cfg =>
{
cfg.AddProfile(new AutoMapperProfile()); //your automapperprofile
});
var mapper = mockMapper.CreateMapper();
And then call then controller like so
var controller = new YourController(imapper:mapper,..otherobjects..);
This way it will serve the purpose or else if you create mock object for IMapper then it will return what you ask it to return.
I'm mocking my repository correctly, but in cases like show() it either returns null so the view ends up crashing the test because of calling property on null object.
I'm guessing I'm supposed to mock the eloquent model returned but I find 2 issues:
What's the point of implementing repository pattern if I'm gonna end up mocking eloquent model anyway
How do you mock them correctly? The code below gives me an error.
$this->mockRepository->shouldReceive('find')
->once()
->with(1)
->andReturn(Mockery::mock('MyNamespace\MyModel)
// The view may call $book->title, so I'm guessing I have to mock
// that call and it's returned value, but this doesn't work as it says
// 'Undefined property: Mockery\CompositeExpectation::$title'
->shouldReceive('getAttribute')
->andReturn('')
);
Edit:
I'm trying to test the controller's actions as in:
$this->call('GET', 'books/1'); // will call Controller#show(1)
The thing is, at the end of the controller, it returns a view:
$book = Repo::find(1);
return view('books.show', compact('book'));
So, the the test case also runs view method and if no $book is mocked, it is null and crashes
So you're trying to unit test your controller to make sure that the right methods are called with the expected arguments. The controller-method fetches a model from the repo and passes it to the view. So we have to make sure that
the find()-method is called on the repo
the repo returns a model
the returned model is passed to the view
But first things first:
What's the point of implementing repository pattern if I'm gonna end up mocking eloquent model anyway?
It has many purposes besides (testable) consisten data access rules through different sources, (testable) centralized cache strategies, etc. In this case, you're not testing the repository and you actually don't even care what's returned, you're just interested that certain methods are called. So in combination with the concept of dependency injection you now have a powerful tool: You can just switch the actual instance of the repo with the mock.
So let's say your controller looks like this:
class BookController extends Controller {
protected $repo;
public function __construct(MyNamespace\BookRepository $repo)
{
$this->repo = $repo;
}
public function show()
{
$book = $this->repo->find(1);
return View::make('books.show', compact('book'));
}
}
So now, within your test you just mock the repo and bind it to the container:
public function testShowBook()
{
// no need to mock this, just make sure you pass something
// to the view that is (or acts like) a book
$book = new MyNamespace\Book;
$bookRepoMock = Mockery::mock('MyNamespace\BookRepository');
// make sure the repo is queried with 1
// and you want it to return the book instanciated above
$bookRepoMock->shouldReceive('find')
->once()
->with(1)
->andReturn($book);
// bind your mock to the container, so whenever an instance of
// MyNamespace\BookRepository is needed (like in your controller),
// the mock will be loaded.
$this->app->instance('MyNamespace\BookRepository', $bookRepoMock);
// now trigger the controller method
$response = $this->call('GET', 'books/1');
$this->assertEquals(200, $response->getStatusCode());
// check if the controller passed what was returned from the repo
// to the view
$this->assertViewHas('book', $book);
}
//EDIT in response to the comment:
Now, in the first line of your testShowBook() you instantiate a new Book, which I am assuming is a subclass of Eloquent\Model. Wouldn't that invalidate the whole deal of inversion of control[...]? since if you change ORM, you'd still have to change Book so that it wouldn't be class of Model
Well... yes and no. Yes, I've instantiated the model-class in the test directly, but model in this context doesn't necessarily mean instance of Eloquent\Model but more like the model in model-view-controller. Eloquent is only the ORM and has a class named Model that you inherit from, but the model-class as itself is just an entity of the business logic. It could extend Eloquent, it could extend Doctrine, or it could extend nothing at all.
In the end it's just a class that holds the data that you pull e.g. from a database, from an architecture point of view it is not aware of any ORM, it just contains data. A Book might have an author attribute, maybe even a getAuthor() method, but it doesn't really make sense for a book to have a save() or find() method. But it does if you're using Eloquent. And it's ok, because it's convenient, and in small project there's nothing wrong with accessing it directly. But it's the repository's (or the controller's) job to deal with a specific ORM, not the model's. The actual model is sort of the outcome of an ORM-interaction.
So yes, it might be a little confusing that the model seems so tightly bound to the ORM in Laravel, but, again, it's very convenient and perfectly fine for most projects. In fact, you won't even notice it unless you're using it directly in your application code (e.g. Book::where(...)->get();) and then decide to switch from Eloquent to something like Doctrine - this would obviously break your application. But if this is all encapsulated behind a repository, the rest of your application won't even notice when you switch between databases or even ORMs.
So, you're working with repositories, so only the eloquent-implementation of the repository should actually be aware that Book also extends Eloquent\Model and that it can call a save() method on it. The point is that it doesn't (=shouldn't) matter if Book extends Model or not, it should still be instantiable anywhere in your application, because within your business logic it's just a Book, i.e. a Plain Old PHP Object with some attributes and methods describing a book and not the strategies how to find or persist the object. That's what repositories are for.
But yes, the absolute clean way is to have a BookInterface and then bind it to a specific implementation. So it could all look like this:
Interfaces:
interface BookInterface
{
/**
* Get the ISBN.
*
* #return string
*/
public function getISBN();
}
interface BookRepositoryInterface()
{
/**
* Find a book by the given Id.
*
* #return null|BookInterface
*/
public function find($id);
}
Concrete implementations:
class Book extends Model implements BookInterface
{
public function getISBN()
{
return $this->isbn;
}
}
class EloquentBookRepository implements BookRepositoryInterface
{
protected $book;
public function __construct(Model $book)
{
$this->book = $book;
}
public function find($id)
{
return $this->book->find($id);
}
}
And then bind the interfaces to the desired implementations:
App::bind('BookInterface', function()
{
return new Book;
});
App::bind('BookRepositoryInterface', function()
{
return new EloquentBookRepository(new Book);
});
It doesn't matter if Book extends Model or anything else, as long as it implements the BookInterface, it is a Book. That's why I bravely instantiated a new Book in the test. Because it doesn't matter if you change the ORM, it only matters if you have several implementations of the BookInterface, but that's not very likely (sensible?), I guess. But just to play it safe, now that it's bound to the IoC-Container, you can instantiate it like this in the test:
$book = $this->app->make('BookInterface');
which will return an instance of whatever implementation of Book you're currently using.
So, for better testability
Code to interfaces rather than concrete classes
Use Laravel's IoC-Container to bind interfaces to concrete implementations (including mocks)
Use dependency injection
I hope that makes sense.
I want to write a unit test that check a stream has been copied on the disk :
The problem is CopyTo method is not virtual so I can't use
inputMemoryStreamMock.Verify(c => c.CopyTo(outputMemoryStreamMock.Object));
and I don't know how to mock a stream :-/
here is my test method :
[TestMethod]
public void Save_Stream_On_DestinationPath()
{
// Arrange
string fileName = "filename.pdf";
DateTime date = new DateTime(2013, 9, 27);
var serverConfigMock = new Mock<IServerConfigurationManager>();
serverConfigMock.Setup(config => config.ReportingBasePath).Returns(#"c:\reportsFolder");
var factoryReportFileResultMock = new Mock<IReportFileResultFactory>();
var timeManagementMock = new Mock<ITimeManagement>();
timeManagementMock.Setup(c => c.GetServerDate()).Returns(date);
var fileSystemMock = new Mock<IFileSystem>();
var fileInfoFactory = new Mock<IFileInfoFactory>();
var directoryInfoBaseMock = new Mock<DirectoryInfoBase>();
var inputMemoryStreamMock = new Mock<Stream>();
var outputMemoryStreamMock = new Mock<Stream>();
var reportFileHelper = new ReportFileHelper(serverConfigMock.Object, factoryReportFileResultMock.Object, fileSystemMock.Object);
inputMemoryStreamMock.Setup(c => c.CanRead).Returns(true);
outputMemoryStreamMock.Setup(c => c.CanWrite).Returns(true);
outputMemoryStreamMock.Setup(c => c.CanWrite).Returns(true);
fileSystemMock.Setup(c => c.FileInfo).Returns(fileInfoFactory.Object);
fileSystemMock.Setup(c => c.File.Create(It.IsAny<string>())).Returns(outputMemoryStreamMock.Object);
fileSystemMock.Setup(c => c.Directory.CreateDirectory(It.IsAny<string>())).Returns(directoryInfoBaseMock.Object);
// Act
reportFileHelper.Save(inputMemoryStreamMock.Object, fileName, timeManagementMock.Object);
// Assert
inputMemoryStreamMock.Verify(c => c.CopyTo(outputMemoryStreamMock.Object));
}
And here is the method to test :
public void Save(Stream portfolioReportFileInfoBase, string destinationName, ITimeManagement timeManagement)
{
string destinationPath = GetDestinationPath(timeManagement);
string destinationFileUri = Path.Combine(destinationPath, destinationName);
FileSystem.Directory.CreateDirectory(destinationPath);
using (var fileStream = FileSystem.File.Create(destinationFileUri))
{
portfolioReportFileInfoBase.CopyTo(fileStream);
}
}
Thank you
My take on a couple of things :
Readability
I'm not sure your test reads very nicely. Why do you declare a fileName variable as though it were important while you don't even assert on it ? Same goes for date. This clutters your test with unneeded detail. Inline values or Anonymous Variables allow for a better signal/noise ratio.
Then why do you set up CreateDirectory() to return something ? You never use that return value, do you ? I suggest you get rid of that and the directoryInfoBaseMock variable. Same with FileInfo and fileInfoFactory. Your test needs to contain the bare minimum to set up the objects you want to verify, and nothing more. If you need to build a deep, complex graph of objects just to test one simple thing, there's generally a problem somewhere.
Design
The second thing that raises an alarm is that Save() mixes multiple language levels. When you read it, it seems to be at the same time about :
Portfolios and reports
Time management
A lot of lower level filesystem stuff
This is often a sign that an object tries to handle too much, violating the Single Responsibility Principle.
What I would do is distribute these responsibilities across separate objects.
Why does Save() need to know about time management ? Sure, we use time management to compute the destination path, but wouldn't it be better aligned with the language level and responsibility level of a Save() method if we directly passed it the destination path instead ?
Why does Save() need to know about portfolios and reports ? Well, there's basically no reason. You could just rename portfolioReportFileInfoBase to... stream.
Save() and GetPath() could then be moved to a separate lower-level filesystem wrapper class (IFileSystem is a perfect candidate), removing the tight coupling between ReportFileHelper and the filesystem.
Don't try to test that your report is written to the disk using mocks. Do it with an integration test. Don't mock types you don't own. Use mocks only to test how your own classes talk to each other. Wrap external libraries/platforms into wrapper objects, and write integration tests at the boundaries of your application to verify that your wrappers play well with those external libraries/platforms.
You'll have to use an isolation framework like TypeMock Isolator or Microsoft Fakes to test this case if you're not willing to change the code of the Save method, since CopyTo can't be mocked by Moq.
You already encapsulated access to the filesystem behind IFileSystem; why not just add a method like CopyStreamToPath?
public void Save(Stream portfolioReportFileInfoBase, string destinationName, ITimeManagement timeManagement)
{
string destinationPath = GetDestinationPath(timeManagement);
string destinationFileUri = Path.Combine(destinationPath, destinationName);
FileSystem.Directory.CreateDirectory(destinationPath);
FileSystem.CopyStreamToPath(portfolioReportFileInfoBase, destinationFileUri);
}
and the test:
fileSystemMock.Verify(c => c.CopyStreamToPath(inputMemoryStreamMock.object, It.IsAny<string>()));
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.
How to mock ObjectContext or ObjectQuery in Entity Framework?
The basic mocking frameworks can only create mocks for interfaces and for abstract classes (but only for abstract/virtual methods).
As the ObjectContext is neither abstract nor interface, it is not so easy to mock it. However, as the concrete model container is generated as partial class (if you use the designer), you can extract the methods/properties you need from it to an interface. In your code, you may use the interface only, that you can mock afterwards.
With the ObjectQuery it is a little bit more easy, as it has a base interface (e.g. IQueryable) that basically contains all the neccessary operations that you usually need (and required for LINQ). So you should expose IQueryable instead of ObjectQuery in your business logic, and you can create mock for that interface.
Other alternative is to hide all data-access related logic into a separate layer (with minimal logic), test this layer with integration tests, and mock it to be able to unit test the other layers.
There are tools (I know only TypeMock) that use the profiling hooks of .NET to generate the mocks. These tools are not limited to mock interfaces or abstract classes, but with them you can mock basically anything, including non-virtual and static methods. With such a tool you don't need to change your business logic in order to allow mocking.
Although this approach is sometimes useful, you have to be aware that extracting the dependencies to interfaces (IoC) is not only helpful for mocking, but also it reduces the dependencies between your components, that has other benefits too.
Personally I like Rhino.Mocks the best from the freeware tools, but we also use TypeMock as well, which is also a great product (but you have to pay for it).
Why can't we just create the actual context object to be used in our tests? Since we don't want our tests to affect the production database, we can always specify a connection string that points to a test database. Before running each test, construct a new context, add the data you will need in your test, proceed with the unit test, then in the test cleanup section, delete all the records that were created during the test. The only side-affect here would be that the auto-increment IDs would be used up in the test database, but since it's a test database - who cares?
I know that most answers regarding this question propose using DI/IoC designs to create interfaces for data contexts etc. but the reason I am using Entity Framework is exactly to not write any interfaces for my database connections, object models, and simple CRUD transactions. To write mock interfaces for my data objects and to write complex queryable objects to support LINQ, defeats the purpose of relying on highly-tested and reliable Entity Framework.
This pattern for unit testing is not new - Ruby on Rails has been using it for a long time and it's worked out great. Just as .NET provides EF, RoR provides ActiveRecord objects and each unit test creates the objects it needs, proceeds with the tests, and then deletes all the constructed records.
How to specify connection string for test environment? Since all tests are in their own dedicated test project, adding a new App.Config file with a connection string for the test database would suffice.
Just think of how much headache and pain this will save you.
I agree with the others you cannot really Mock ObjectContext. You should use EF DbContext because you can mock the underlying DbSet There are quite a lot of post how to do that. So I won't write how to do it. However if you absolutely must use ObjectContext (for some reason) and you want to Unit test it you can use InMemory database.
First install this Nuget package: Effort (Entity Framework Fake ObjectContext Realization Tool), which uses NMemory as the database. Install Effort.EF6 package:
PM> Install-Package Effort.EF6
using System;
using System.Data.Common;
using System.Data.Entity;
using System.Data.Entity.Core.Objects;
using System.Data.Entity.Infrastructure;
using Effort;
public class DbContextHelper
{
//Fake object you can drop this if you are using your own EF context
private class DbObject
{
public Guid Id { get; set; }
public string Name { get; set; }
}
//Fake EF context you can switch with you own EF context
private class FakeDbContext : DbContext
{
public FakeDbContext(DbConnection connection)
: base(connection, true) { }
public virtual DbSet<DbObject> DbObjects { get; set; }
}
private FakeDbContext _dbContext;
public DbContextHelper()
{
//In memory DB connection
DbConnection effortConnection = DbConnectionFactory.CreatePersistent("TestInstanceName");
_dbContext = new FakeDbContext(effortConnection);
}
//You can expose your context instead of the DbContext base type
public DbContext DbContext => _dbContext;
public ObjectContext ObjectContext => ((IObjectContextAdapter)_dbContext).ObjectContext;
//Method to add Fake object to the fake EF context
public void AddEntityWithState(string value, EntityState entityState)
{
DbContext.Entry(new DbObject() { Id = Guid.NewGuid(), Name = value }).State = entityState;
}
}
Usage:
DbContextHelper _dbContextHelper = new DbContextHelper();
_dbContextHelper.AddEntityWithState("added", System.Data.Entity.EntityState.Added);
_dbContextHelper.AddEntityWithState("added", System.Data.Entity.EntityState.Modified);
var objs = _dbContextHelper.ObjectContext.GetObjectStateEntries(EntityState.Modified | EntityState.Added);
There you are you have your object in memory DB.