Testcontainers Implementation for Functional Tests

Summary

Successfully migrated functional tests from in-memory database to Testcontainers with SQL Server 2022. This provides a more realistic testing environment that matches production database behavior.

Changes Made

1. Package References

Added to Directory.Packages.props:

xml

<PackageVersion Include="Testcontainers" Version="4.3.0" />
<PackageVersion Include="Testcontainers.MsSql" Version="4.3.0" />

Updated tests\Clean.Architecture.FunctionalTests\Clean.Architecture.FunctionalTests.csproj:

Removed: Microsoft.EntityFrameworkCore.InMemory
Added: Testcontainers and Testcontainers.MsSql

2. CustomWebApplicationFactory

File: tests\Clean.Architecture.FunctionalTests\CustomWebApplicationFactory.cs

Key changes:

Implements IAsyncLifetime for proper async initialization/cleanup
Creates a SQL Server container using MsSqlBuilder
Uses SQL Server 2022 image: mcr.microsoft.com/mssql/server:2022-latest
Applies EF Core migrations instead of EnsureCreated()
Each test run gets a fresh containerized SQL Server instance

csharp

private readonly MsSqlContainer _dbContainer = new MsSqlBuilder()
  .WithImage("mcr.microsoft.com/mssql/server:2022-latest")
  .WithPassword("Your_password123!")
  .Build();

3. Test Configuration

Tests now:

Use real SQL Server running in Docker containers
Apply actual EF Core migrations (matches production)
Run against isolated database instances (parallel test safety)
Clean up containers automatically after tests complete

Benefits

? Realistic Testing: Tests run against actual SQL Server, not in-memory provider
? Migration Testing: Validates that migrations work correctly
? Production Parity: Database behavior matches production environment
? Isolation: Each test class gets its own containerized database
? Automatic Cleanup: Containers are disposed after tests complete

Requirements

Docker Desktop must be running on the development machine
Tests take slightly longer (~10-13 seconds vs instant with in-memory)
First run downloads SQL Server 2022 Docker image (~1.5 GB)

Test Results

All 18 tests passing:

? Unit Tests: 15 tests
? Functional Tests: 3 tests
? Total Duration: ~12 seconds

Usage

Run tests normally:

bash

dotnet test

Or specifically for functional tests:

bash

dotnet test tests\Clean.Architecture.FunctionalTests\Clean.Architecture.FunctionalTests.csproj

Notes

Tests use the "Testing" environment configuration
SQL Server password: Your_password123! (only for test containers)
Container lifecycle managed by xUnit's IAsyncLifetime
Containers are automatically cleaned up even if tests fail