Mocks, Stubs, and Fakes
Differentiate between test doubles: mocks, stubs, fakes, and dummies, and understand their roles in testing.
What are Test Doubles?
When testing a class, it often depends on other classes. These "dependencies" can make tests tricky! Test doubles are stand-in objects that mimic the behavior of real dependencies.
They help isolate the code you're testing, making your tests faster, more reliable, and easier to write.
Why Do We Need Them?
Imagine testing a class that sends emails or talks to a database. You don't want your tests to:
- Actually send emails (spam!).
- Slow down by hitting a real database.
- Depend on external services that might be unavailable.
Test doubles solve these problems by providing controlled, predictable replacements.