Unit Tests in .Net Core – code and more!

There are many tools to write unit tests. here is what I like to use:

Mocking: FakeItEasy (https://fakeiteasy.github.io/).
Assert: Shouldly (https://github.com/shouldly/shouldly)
Stubs: AutoFixture (https://github.com/AutoFixture/AutoFixture)

FakeItEasy for mocks

I really prefer FakeItEasy over Moq and others for two reasons. The first reason is that a mock is a real object and it does not require .Object everywhere. The 2nd reason the clean and easy setup and verification.

I prefer this code:

A.CallTo(() => service.Setup.SendAsync(A<int>._)).Returns(3);

over:

service.Setup(x => x.SendAsync(It.IsAny<int>())).ReturnsAsync(3);

Shouldly for asserts

I really prefer Shouldly because typical Assert is just plain ugly. it might be a personnel preference, but I just like that code

cart.Status.ShouldBe(status);
count.ShouldBe(200);

over:

Assert.Equal(cart.Status, status);
Assert.Equal(count, 200);

AutoFixture for stubbing

The most important piece for me is autoFixture which is a great way to stub object.

No more coding huge setup code just for initialize objects. with AutoFixture you can inject your objects into the test and will be automatically populated with data. you can customize the data if you wish.


[Theory, AutoFill]
public async void CompleteAsync_ShouldNotCompleteOrder_WhenCartIsOld(ShippingCart cart)
{
             //test code
}
 

//custom code to return a certain value for a certain property.
//in this case, if propery name is Email, the value should end with @email.com
public class EmailBuilder : ISpecimenBuilder
{
    public object Create(object request, ISpecimenContext context)
    {
        var property = request as PropertyInfo;

        return property?.Name == "Email" ? (object) $"{Guid.NewGuid()}@email.com" : new NoSpecimen();
    }
}