Sometimes you want to test a class without using its real dependencies. That’s where test doubles come in.
🪀 Types of Test Doubles
- Stub: Returns fixed data (no real logic)
- Fake: Simple working implementation (not production-ready)
- Mock: Checks if certain actions happened (like method calls)
🔧 Mocking Libraries
- Moq is the most popular for .NET
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var mockLogger = new Mock<ILogger>();
mockLogger.Setup(l => l.Log(It.IsAny<string>())).Verifiable();
📝 Why Mock?
- Test only your code, not outside systems (like databases or web APIs)
- Make tests run faster and more reliably
💡 Try It!
Install Moq with:
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dotnet add package Moq
And try mocking an interface in your tests.
Next: Test-driven development (TDD)!
