testcontainers-dotnet VS AutoFixture

Testcontainers

Like others said, it's better to test with an actual database. I recommend using Testcontainers (https://dotnet.testcontainers.org), you can even create multiple instances so your tests can run in parallel independently.

To launch a container in code we will use Testcontainers. Testcontainers is a library that is built on top of the .NET Docker remote API and provides a lightweight implementation to support your test environment in all circumstances. This library supports pre-defined packages for containers or you can use your .dockerfile. We will use a pre-defined package for LocalStak. LocalStack is a cloud service emulator that runs in a single container for AWS service. LocalStack supports a growing number of AWS services.

Bogus - For creating fake data Verify - Snapshot testing for .NET MELT - For testing ILogger usage Stryker - Mutation Testing for .NET TestContainers - run docker programmatically in integration tests

.NET Shop using SQL Server here, but I think something similar to what we do can apply to any stack. We use TestContainers [1] to spin up a container with SQL Server engine running on it. Then use FluentMigrator [2] to provision tables and test data to run XUnit integration tests against. This has worked remarkably well.

[1] https://dotnet.testcontainers.org/

Yes, it does feel like some of the "standard stuff" in other more nuanced languages are missing (especially miss AutoFixture ngl). Some of those are a conscious decison by the golang team for example.

Our first test is very easy, I like to name my tests as MethodName_GivenCondition_ShouldExpectedResult to follow the pattern, I have added GetById_GivenRecordDoesNotExist_ShouldReturnNull and I am going to leavarage excellent AutoFixture to get a new Guid as parameter. For this test we don't need arrange part, we would skip to the act and then assert. For Assertion I am going to use FluentAssertions. For this test we need to assert the returned result is null.

The next test to talk about, is that if this was a bank, we would have multiple customers, who can hold multiple accounts that we need to calculate the interest for. You could manually construct these objects if you want, but I'm going to use a package called AutoFixture to make life easier.

AutoFixture is an amazing library that simplifies the process of creating test data in .NET. If for some reason you don't use this fantastic tool, it's time to consider it. Today, I'm going to share some tips for using AutoFixture that will be beneficial for developers of all skill levels. Let's get started!

AutoFixture

Ensuring that your test is still readable and not bloated by the setup of those variables may be quite a challenge but hopefully no more with AutoFixture, let's see how!

One neat library for creating and generating test data is AutoFixture.  The creators describe it as follows:

First time I heard of Bogus, looks interesting, been using AutoFixture for those will definitely take a look at it.