Testing — Unit & Integration Test Patterns

Granit.Testing eliminates the 50+ lines of boilerplate that every test project repeats: DI setup, NSubstitute mocks for IClock / ICurrentTenant / ICurrentUserService / IGuidGenerator, and EF Core context wiring. New test setup drops to under 10 lines.

Package structure

• DirectoryGranit.Testing/ Fakes, fixture, Bogus generators

  • Granit.Testing.EntityFrameworkCore InMemory + SQLite DbContext factories

Package	Role	Depends on
Granit.Testing	GranitTestFixture, fakes, GranitWebApplicationFactory, Bogus generators	Granit, Granit.Users, Granit.Timing, Granit.Guids, Bogus
Granit.Testing.EntityFrameworkCore	InMemoryDbContextFactory, SqliteDbContextFactory, AddGranitTestDbContext	Granit.Testing, Granit.Persistence, EF Core InMemory, EF Core Sqlite

Dependency graph

graph TD
    T[Granit.Testing] --> C[Granit]
    T --> S[Granit.Users]
    T --> Ti[Granit.Timing]
    T --> G[Granit.Guids]
    TEF[Granit.Testing.EntityFrameworkCore] --> T
    TEF --> P[Granit.Persistence]

AsyncLocal-backed fakes

All fakes store state in AsyncLocal<T>. This means each xUnit test gets isolated state even when sharing a fixture via IClassFixture<T> — no cross-test pollution when tests run in parallel.

Fake	Interface	Default value
FakeCurrentTenant	ICurrentTenant	Unavailable (no tenant)
FakeCurrentUser	ICurrentUserService	Authenticated user "test-user-001"
FakeClock	IClock	2026-01-15T10:00:00Z
FakeGuidGenerator	IGuidGenerator	Sequential deterministic GUIDs

FakeCurrentTenant

FakeCurrentTenant tenant = new();
tenant.Id = tenantId;
tenant.Name = "Acme Corp";

// Scope-based (restores previous state on Dispose)
using (tenant.Change(otherTenantId, "Other Corp"))
{
    // tenant.Id == otherTenantId
}
// tenant.Id == tenantId (restored)

FakeClock

FakeClock clock = new(); // 2026-01-15T10:00:00Z

clock.Advance(TimeSpan.FromHours(2)); // Now == 12:00
clock.Now = new DateTimeOffset(2030, 1, 1, 0, 0, 0, TimeSpan.Zero); // explicit

FakeGuidGenerator

// Queue mode: return exact GUIDs for assertions
FakeGuidGenerator gen = new();
gen.Enqueue(knownGuid);
gen.Create(); // returns knownGuid

// Sequential mode: deterministic GUIDs when queue is empty
gen.Create(); // 00000001-0000-0000-0000-000000000000
gen.Create(); // 00000002-0000-0000-0000-000000000000

GranitTestFixture

Bootstraps the full Granit module graph and replaces core services with fakes.

public sealed class CachingTests : IAsyncDisposable
{
    private readonly GranitTestFixture<GranitCachingModule> _fixture = new();

    [Fact]
    public async Task Cache_Service_Is_Resolved()
    {
        await _fixture.BuildAsync();

        var cache = _fixture.GetRequiredService<IFusionCache>();
        cache.ShouldNotBeNull();
    }

    // Customize fakes per test (AsyncLocal isolation)
    [Fact]
    public async Task Tenant_Aware_Cache()
    {
        _fixture.Tenant.Id = Guid.NewGuid();
        await _fixture.BuildAsync();
        // ...
    }

    public async ValueTask DisposeAsync() => await _fixture.DisposeAsync();
}

GranitWebApplicationFactory

For endpoint integration tests with a real HTTP pipeline.

public sealed class ApiTests : IClassFixture<GranitWebApplicationFactory<Program>>
{
    private readonly GranitWebApplicationFactory<Program> _factory;

    public ApiTests(GranitWebApplicationFactory<Program> factory)
    {
        _factory = factory;
    }

    [Fact]
    public async Task Get_Returns_Ok()
    {
        _factory.User.UserId = "admin-001";
        _factory.User.AddRole("Admin");

        HttpClient client = _factory.CreateClient();
        HttpResponseMessage response = await client.GetAsync("/api/items");

        response.StatusCode.ShouldBe(HttpStatusCode.OK);
    }
}

EF Core factories

SQLite (recommended)

// Real SQL semantics — catches FK violations, type mismatches
using SqliteDbContextFactory<AppDbContext> factory = new();

using AppDbContext context = factory.CreateContext();
context.Orders.Add(new Order { Title = "Test" });
await context.SaveChangesAsync();

// Audit fields set automatically by interceptors
entity.CreatedAt.ShouldBe(factory.Clock.Now);

InMemory (interceptors only)

// Fast but no SQL translation — use only for interceptor/logic tests
InMemoryDbContextFactory<AppDbContext> factory = new();

using AppDbContext context = factory.CreateContext();
// ...

Caution

The InMemory provider does not enforce foreign keys, transactions, or SQL semantics. Tests will pass here but may fail on PostgreSQL/SQL Server. Use SqliteDbContextFactory unless you have a specific reason not to.

DI integration

// Inside GranitTestFixture — registers DbContext in the DI container
await fixture.BuildAsync(services =>
    services.AddGranitTestDbContext<AppDbContext>());

var context = fixture.GetRequiredService<AppDbContext>();

Bogus generators

GranitFaker

Static factory methods for generating realistic fake data.

FakeCurrentUser user = GranitFaker.CurrentUser().Generate();
// user.UserId = "a3f1b2c4-...", user.Email = "[email protected]"

FakeCurrentTenant tenant = GranitFaker.Tenant().Generate();
// tenant.Id = Guid, tenant.Name = "Acme Corp"

Entity audit extensions

// Populate audit fields on domain entities
List<Invoice> invoices = new Faker<Invoice>()
    .RuleForFullAudit()          // Id, CreatedAt/By, ModifiedAt/By, IsDeleted
    .RuleForMultiTenant(tenantId) // TenantId
    .RuleFor(i => i.Amount, f => f.Finance.Amount())
    .Generate(50);

Extension	Constraint	Fields populated
RuleForCreationAudit<T>()	T : CreationAuditedEntity	Id, CreatedAt, CreatedBy
RuleForAudit<T>()	T : AuditedEntity	+ ModifiedAt, ModifiedBy
RuleForFullAudit<T>()	T : FullAuditedEntity	+ IsDeleted, DeletedAt, DeletedBy
RuleForMultiTenant<T>()	T : IMultiTenant	TenantId