Adding Integration Tests

Previous: Adding Other Endpoints

Setup

To start making integration tests for our NotesController, I'd suggest making a new xUnit Unit Test project called NotesApp.IntegrationTests. Use the same versions of Microsoft.NET.Test.Sdk, xunit, xunit.runner.visualstudio, and FluentAssertions as the NotesApp.Tests project.

For integration tests, we're going to need a test server to to run our endpoints on. Add Microsoft.AspNetCore.TestHost as a NuGet dependency to NotesApp.IntegrationTests.

Because setup of a test server is going to be very similar across controllers, let's add a utility class for setting everything up. Create a new directory, Utils, and make a new class, HttpClientUtils, with the following:

public static class HttpClientUtils
{
    public static HttpClient CreateClient()
    {
        var server = new TestServer(
            new WebHostBuilder()
                .UseStartup<TestStartup>()
        );
        return server.CreateClient();
    }
}

TestStartup is a class that simply extends Startup from NotesApp, and allows us to override specific features during testing.

The HttpClient return value of CreateClient is what will be used for making calls to our endpoints.

Within Startup of NotesApp, add

services.AddRouting(opt => opt.LowercaseUrls = true);

just above

services.AddMvc()

within ConfigureServices.

This gives us the flexibility of not having to use title case URLs when hitting our endpoints.

---

Writing the Tests

Within NotesApp.IntegrationTests, create a new directory, Controllers, and add a new class, NotesControllerTests.

Add the following to NotesControllerTests:

private const string NotesEndpoint = "/api/notes";
private readonly HttpClient _client;

public NotesControllerTests()
{
    // Staticly imported from HttpClientUtils
    _client = CreateClient();
}

Let's begin with a simple example. Add a test that will make sure that calling PostAsync(Note note) with an invalid note will return a BadRequest status code. The HttpStatusCode enum can be quite useful here. You can call to the endpoint using:

await _client.PostAsJsonAsync<Note>(NotesEndpoint, null);

We've tested for the CreatedAtRoute in our unit tests, so let's write our integration test now. When the controller returns a CreatedAtRouteResult, it puts the location of the Note into response.Headers.Location in the form of a URI. Verify that the path is correct. To retrieve the model from the response, you can use the following:

var actual = await response.Content.ReadAsAsync<Note>();

Add tests for the remaining endpoints and test cases that we covered with our unit tests.

Git Tag: adding-integration-tests

Up Next: Adding a Persistence Layer