Automated Testing in .NET: Continuous Confidence with Less Rework

In complex systems and critical APIs, testing is more than just verifying code — it's about ensuring business rules remain intact as the system evolves. And in the .NET ecosystem, we have powerful tools to make that happen. When working with .NET 8, I follow an approach that combines clarity, performance, and real value for the product team: Unit Testing (xUnit + Moq or NSubstitute) Focused on pure business logic, especially in domain classes and validations. No external dependencies: fast, isolated, and deterministic. I use FluentAssertions for more readable and expressive assertions. Integration Testing (Testcontainers + real database) I spin up real databases (e.g., PostgreSQL, SQL Server) using disposable containers during tests. This covers repository logic, migrations, and actual infrastructure config. It prevents false positives caused by over-mocking. Contract Testing (Pact) Ensures that microservices communicate with the same expectations, even when deployed independently. The consumer generates a contract; the provider validates it — CI enforces consistency. Reduces the “it worked on my machine” syndrome across teams. Additional practices that matter: Realistic test data with Bogus or AutoFixture Coverage reports with Coverlet integrated into CI Parallel test execution with xUnit for faster feedback Validation on PRs via GitHub Actions or Azure DevOps pipelines The result: Safer refactoring More reliable deployments A team that feels confident and focused on delivering value — not fixing bugs

May 8, 2025 - 01:37

Automated Testing in .NET: Continuous Confidence with Less Rework

In complex systems and critical APIs, testing is more than just verifying code — it's about ensuring business rules remain intact as the system evolves. And in the .NET ecosystem, we have powerful tools to make that happen.

When working with .NET 8, I follow an approach that combines clarity, performance, and real value for the product team:

Unit Testing (xUnit + Moq or NSubstitute)

Focused on pure business logic, especially in domain classes and validations.
No external dependencies: fast, isolated, and deterministic.
I use FluentAssertions for more readable and expressive assertions.

Integration Testing (Testcontainers + real database)

I spin up real databases (e.g., PostgreSQL, SQL Server) using disposable containers during tests.
This covers repository logic, migrations, and actual infrastructure config.
It prevents false positives caused by over-mocking.

Contract Testing (Pact)

Ensures that microservices communicate with the same expectations, even when deployed independently.
The consumer generates a contract; the provider validates it — CI enforces consistency.
Reduces the “it worked on my machine” syndrome across teams.

Additional practices that matter:

Realistic test data with Bogus or AutoFixture
Coverage reports with Coverlet integrated into CI
Parallel test execution with xUnit for faster feedback
Validation on PRs via GitHub Actions or Azure DevOps pipelines

The result:

Safer refactoring
More reliable deployments
A team that feels confident and focused on delivering value — not fixing bugs