Integration tests

The rule

Integration tests use the real database engine, built from the real migrations, and every test gets its own database. No test can see another test's changes, and nothing is written to disk.

Steps

1. Repository tests: make the test class sealed and IDisposable, create private readonly MovieReviewsTestDatabase database = new(); and dispose it. Use this.database.Repository, and this.database.Context to find known rows.
2. Find rows by their known values, not by position.
3. For time-dependent results, assert against this.database.TimeProvider.
4. Presentation tests: create a new application host per test class instance, pass settings in through its constructor, and make real requests (in Lambda, real calls to the handler). Assert the status code, then the body.
5. Override settings in memory through the host's constructor, never by editing appsettings files or leaving environment variables set.
6. The details of this template's application host are in presentation-integration-tests.

Example

// tests/Infrastructure.Tests.Integration/Databases/MovieReviews/EntityFrameworkMovieReviewsRepositoryTests.cs
public sealed class EntityFrameworkMovieReviewsRepositoryTests : IDisposable
{
    private readonly MovieReviewsTestDatabase database = new();

    public void Dispose()
    {
        this.database.Dispose();
    }

    [Fact]
    public async Task GetAuthorById_ShouldReturn_Author()
    {
        // Arrange
        var repository = this.database.Repository;
        using var tokenSource = new CancellationTokenSource();
        var token = tokenSource.Token;
        var author = this.database.Context.Authors.First(a => a.FirstName == "One");

        // Act
        var result = await repository.GetAuthorById(author.Id, token);

        // Assert
        _ = result.ShouldNotBeNull();
        result.Reviews.Count.ShouldBe(3);
    }
}

Don't

• Use the EF Core InMemory provider. It isn't relational and lets through queries SQLite rejects.
• Share one database across tests with IClassFixture or ICollectionFixture.
• Write to movie-reviews.db or any file.
• Depend on test order.

Check

dotnet test tests/Infrastructure.Tests.Integration
dotnet test tests/Presentation.Tests.Integration