Unit vs. Integration Tests

Notes

A unit test tests your code without your code’s dependencies, whereas an integration test tests your code integrated with its dependencies.

Dependencies include:

• WordPress – as it’s outside of your code.
• An external API – such as Stripe, PayPal, a help desk, weather, population, demographics, etc.
• An external package you embedded into your plugin, theme, or application, such as Guzzle, CMB2, Fulcrum’s Extender module, or Fulcrum’s Config module.
• A reusable module that you or your company built and tested separately.

In a unit test, you are testing the expected behavior for the given conditions of your code. You fake out or simulate the dependencies. We can do this using:

• Brain Monkey
• Mockery
• and others.

Then after you complete your unit tests and you are confident in your code, you build your integration tests. Here you are testing your code’s interactions with its different dependencies.