Table of Contents General Official Assertions Spies Stubs Mocks Fakes More Handling promises

• spies: function that records arguments for all its calls (also: return value, this and exception thrown)
  • can wrap methods that already exists
  • can also be anonymous
• stubs: functions (spies) with pre-programmed behavior
• mocks: functions (spies) with pre-programmed
  • behavior (like stubs)
  • expectations

Definition:

• spies: offer information about function calls, without affecting their behavior
• stubs: completely replace the function:
  • return a specific value
  • throw an exception
• mocks: combining both spies and stubs
• fakes: ?

API

2 ways:

• use native API
• use sinon-chai plugin

API: Test stubs are functions (spies) with pre-programmed behavior.

API Mocks are fake methods (like spies) with pre-programmed behavior (like stubs) as well as pre-programmed expectations. A mock will fail your test if it is not used as expected.

The rule of thumb is: if you wouldn’t add an assertion for some specific call, don’t mock it. Use a stub instead.

API

Sinon stub promise Sinon as promise