Unable to load/reference appsettings.json when integration testing an ASP.NET Core WebApi app using MVC.Testing

Hi there 👋

I’m trying to do a basic integration test for a very simple ASP.NET Core WebApi project.

I’m leveraging the WebApplicationFactory class and when I do this, my appsettings.json file located in my test project is not getting used. The appsettings.development.json file in the WebApi project (the SUT) is getting used.

I’ve tried to use Source Link/Source Debugging using the MS Symbol Server to step through the WebApplicationFactory class to figure out why/what. It’s a bit hard to grok.

I even sorta tried to use the TEST_CONTENTROOT_APPNAME trick/hack I noticed in the source code but I couldn’t get that to work properly (I think i’m not correctly adding this via my custom protected override IWebHostBuilder CreateWebHostBuilder() method early on in the bootstrapping).

Anyways -> can anyone (repo members?) please provide some clues to how I can use my own appsettings.json locally in my test project … and not the ones in the SUT.

Why?

SUT appsettings.development.json : db points to localhost Test project appsettings.json : db will point to some ‘dev’ server in the cloud.

[poke]

So instead of passing around a DBContext we pass around a ConnectionString

Then you can just inject the connection string POCO there. You have the full DI container, so do whatever you need to do 😉

Also in your test above, that POST will mutate/change the DB. Why aren’t you rolling that back? Or you usually would but this is just some quick and simple example code?

This is an integration test on a separate database which will be created only for the test execution and dropped completely afterwards. So I don’t really care about left over stuff, as long as it does not conflict with other tests. And I try to design my tests in a way that they don’t. But of course, that’s totally up to you.

So do you mean something like this?

Actually, I was thinking more about something like this:

public static class TestHelper
{
    public IConfiguration GetTestConfiguration()
        =>  new ConfigurationBuilder()
            .AddJsonFile("integrationsettings.json")
            .Build();
}

// and then inside of the TestApplicationFactory
builder.ConfigureAppConfiguration(config =>
{
    config.AddConfiguration(TestHelper.GetTestConfiguration());
});

That way, I do not need to depend on the full web application factory (which means that it spawns the whole application for integration tests) and can just use the config directly in a less-than-full integration test.

So inside of another test, that is not a full integration test, you could do it like this:

[Fact]
public Task AddItem()
{
    // arrange
    var connectionString = TestHelper.GetTestConfiguration().GetConnectionString("DefaultConnection");
    var service = new ExampleService(connectionString);

    // act
    service.Add(new Item { Foo = "Bar" });

    // assert
    using (var db = new SqlConnection(connectionString))
    {
        // verify stuff
    }
}

[PureKrome]

Thanks for the help! Much appreciated. Yep, question has been answered.