C#•2y ago

Integration testing a web API [Answered]

Just for the sake of the learning experience, I wanna write some integration tests for the endpoints in my web API. What's the typical way of doing this? Do you have to use some kind of HttpClient setup to call the API as if using HTTP or is there some better way of just testing the endpoints individually? For context, all of my endpoints return Task<IResult>, so I (probably) can't just test the direct return value of each endpoint method.

56 Replies

pox•2y ago

Do you want to test the Http calls? Or do you just want to test the logic of the endpoint? We do both, we start up a testhost and do http calls at it. We also allow you to replace instances with mocks if you want to not have any external calls etc. You can also just create a Controller with all the dependencies and use the functions directly

Thinker•2y ago

Test the logic of the endpoint I don't think I care about testing the HTTP calls...? I suppose I can do something like

var result = await Endpoints.GetSomethingAsync();
var ok = Assert.IsType<OkObjectResult>(result);
Assert.Equal(StatusCodes.Status200OK, ok.StatusCode);
Assert.Equal(expected, ok.Value);

var result = await Endpoints.GetSomethingAsync();
var ok = Assert.IsType<OkObjectResult>(result);
Assert.Equal(StatusCodes.Status200OK, ok.StatusCode);
Assert.Equal(expected, ok.Value);

Seems like otherwise you need to test the entire pipeline with WebApplicationFactory

pox•2y ago

Yeah

Thinker•2y ago

That's... annoying Is there at least some way to not have to write the endpoint route and instead have it be inferred from the method?

pox•2y ago

We generate a client from the openapi spec that has models and routes etc, might be very overkill I've seen ppl make consts and helper methods for setting and calling the routes

Thinker•2y ago

... you can't access Microsoft.AspNetCore.Http.Result.OkObjectResult??? why tf Why do you need to do so much stuff to write some tests catlost

pox•2y ago

Most stuff you need to setup once, then the actual tests are small Are you doing the httpclient route?

Patrick•2y ago

i don't know what you're actually trying to achieving by testing this all you seem to be doing is testing asp.net core

Thinker•2y ago

I wanna test my endpoint methods?

Patrick•2y ago

what's the goal of the test

pox•2y ago

Test the endpoint methods

Patrick•2y ago

that's not a goal that's an activity

Thinker•2y ago

... testing that they do the correct thing

Starlk•2y ago

to see if they work as expected?

Patrick•2y ago

people writing pointless tests lead to maintaining absolutely worthless code, if you're doing this for experience learn what makes a good test

Thinker•2y ago

wow, thanks catpog

Patrick•2y ago

not sure if sarcasm, the point being most people end up preaching 100% code coverage and end up spamming tests which have little worth in the bigger picture of actually maintaining a project

Thinker•2y ago

Well what should I be doing then? I wanna learn how to write tests for stuff, because that's what I've seen other people do.

pox•2y ago

Agreed, doing tests for testing sake is bad

Thinker•2y ago

I can absolutely see that

Patrick•2y ago

that depends on the project - imitating unit tests just because you've seen them defeats the purpose of unit tests

pox•2y ago

But we tend to unit test logic heavy code and do some integration tests for the "code clue"

Thinker•2y ago

This is literally my first web API project and it's ridiculously small, really I don't need tests but I thought it'd be a good opportunity to learn anyway

Patrick•2y ago

ok but you've built the API to do something, yes?

Thinker•2y ago

Yes

Patrick•2y ago

and you'd have an idea of who would consume the API?

Thinker•2y ago

Yes

Patrick•2y ago

the integration tests should be modelled around that - "as a user of this API, when I do X I should get Y and be able to do Z"

Thinker•2y ago

Okay so I shouldn't be testing the individual endpoint methods but rather the HTTP routes?

Patrick•2y ago

ive come in with a little less context to be honest, but if you're going for an integration test that sounds more like what you should be doing

Thinker•2y ago

Right

Mayor McCheese•2y ago

I usually do both tbh My primary motivations for web application factory tests is to test I get 401s back This can still be done with controller tests in a manner

Thinker•2y ago

Okay so I'm getting an exception System.InvalidOperationException : The server has not been started or no web application was configured. when calling WebApplicationFactory<TEntryPoint>.CreateClient() why is this so damn hard catlost

pox•2y ago

https://docs.microsoft.com/en-us/aspnet/core/test/integration-tests?view=aspnetcore-6.0

Integration tests in ASP.NET Core

Learn how integration tests ensure that an app's components function correctly at the infrastructure level, including the database, file system, and network.

Thinker•2y ago

That's the article I'm reading Okay now it works when just using the first example of var application = new WebApplicationFactory<Program>()

pox•2y ago

ingame currently so cant look 😄

Thinker•2y ago

This is my thing currently

[Fact]
public async Task GetListsAsync_ReturnsIds() {
    var ids = Enumerable.Range(0, 10)
        .Select(_ => Guid.NewGuid())
        .ToArray();

    Mock<ITodoService> todoServiceMock = new();
    todoServiceMock
        .Setup(x => x.GetListIdsAsync())
        .ReturnsAsync(ids);
    var todoService = todoServiceMock.Object;

    var a = new WebApplicationFactory<Program>()
        .WithWebHostBuilder(builder => builder
            .ConfigureServices(services => services
                .AddScoped(todoService)));
    var client = a.CreateClient();

    var response = await client.GetAsync("/getLists");
    Assert.True(response.IsSuccessStatusCode);
    var value = await response.Content.ReadFromJsonAsync<List<Guid>>();
    Assert.Equal(ids, value);
}

[Fact]
public async Task GetListsAsync_ReturnsIds() {
    var ids = Enumerable.Range(0, 10)
        .Select(_ => Guid.NewGuid())
        .ToArray();

    Mock<ITodoService> todoServiceMock = new();
    todoServiceMock
        .Setup(x => x.GetListIdsAsync())
        .ReturnsAsync(ids);
    var todoService = todoServiceMock.Object;

    var a = new WebApplicationFactory<Program>()
        .WithWebHostBuilder(builder => builder
            .ConfigureServices(services => services
                .AddScoped(todoService)));
    var client = a.CreateClient();

    var response = await client.GetAsync("/getLists");
    Assert.True(response.IsSuccessStatusCode);
    var value = await response.Content.ReadFromJsonAsync<List<Guid>>();
    Assert.Equal(ids, value);
}

It works and I guess it's fairly compact

pox•2y ago

We use something like this to move the whole host stuff outside the test https://docs.microsoft.com/en-us/aspnet/core/test/integration-tests?view=aspnetcore-6.0#customize-webapplicationfactory

Integration tests in ASP.NET Core

Learn how integration tests ensure that an app's components function correctly at the infrastructure level, including the database, file system, and network.

Thinker•2y ago

How would you add a mock service to that?

pox•2y ago

We use some logic so you can replace services at startup of the host

Thinker•2y ago

Also when you say "we", do you mean your company?

pox•2y ago

Yeah Swedish digital healthcare Also do you need to mock the todoSerivce? Might be worth doing a

Thinker•2y ago

wait we're both swedes catsip

again more of a case of just wanting to try what I've seen others do because I wanna learn Plus it's kind of useful since some endpoints only need to call specific methods in the service.

pox•2y ago

Are you using xunit?

Thinker•2y ago

yep

pox•2y ago

If you want we could perhaps jump in to a call and look at it, maybe not tonight tho You could also do something simplier

Thinker•2y ago

Mind showing an example?

pox•2y ago

You could follow this and do a CustomWebApplicationFactory https://docs.microsoft.com/en-us/aspnet/core/test/integration-tests?view=aspnetcore-6.0#customize-webapplicationfactory

Integration tests in ASP.NET Core

Learn how integration tests ensure that an app's components function correctly at the infrastructure level, including the database, file system, and network.

Thinker•2y ago

also completely unrelated, is your pfp literally the ica logo?

pox•2y ago

Yeah

Thinker•2y ago

love it

pox•2y ago

Maybe something like this

public class CustomWebApplicationFactory<TStartup>
    : WebApplicationFactory<TStartup> where TStartup : class
{

    private readonly Mock<ITokenService> _mock;

    public CustomWebApplicationFactory(Mock<ITokenService> mock)
    {
        _mock = mock;
    }

    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        builder.ConfigureServices(services =>
        {
            services.ReplaceWithInstance(_mock.Object);
        });
    }
}

public class CustomWebApplicationFactory<TStartup>
    : WebApplicationFactory<TStartup> where TStartup : class
{

    private readonly Mock<ITokenService> _mock;

    public CustomWebApplicationFactory(Mock<ITokenService> mock)
    {
        _mock = mock;
    }

    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        builder.ConfigureServices(services =>
        {
            services.ReplaceWithInstance(_mock.Object);
        });
    }
}

Im sure there are better ways You could also just move some logic to the ctor a function to keep it simple

    Mock<ITodoService> todoServiceMock = new();
    var a = new WebApplicationFactory<Program>()
        .WithWebHostBuilder(builder => builder
            .ConfigureServices(services => services
                .AddScoped(todoServiceMock.Object)));

    Mock<ITodoService> todoServiceMock = new();
    var a = new WebApplicationFactory<Program>()
        .WithWebHostBuilder(builder => builder
            .ConfigureServices(services => services
                .AddScoped(todoServiceMock.Object)));

Do this and save the application and mock in a readonly field I gtg This got messy but 😄

Thinker•2y ago

I need to go to sleep anyway Thanks for the assistance catsip

Mayor McCheese•2y ago

Net6? If you’re using top level statements there’s some things you have to do for web application factory

Thinker•2y ago

yes

Accord•2y ago

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Integration testing a web API [Answered]