describe statements are used to identify a suite, which are a group of related specs. It provides a level of indentation.

it statements are used to identify a specification ie a container for feature we are testing. If all expectations within a spec return true, it passes. If any of the expectations were to return false, the spec would fail.

expect is the launching point of any test. It accepts a single value called the actual function.

matcher The comparison method used is called the matcher and is chained after the call to expect. We pass the expected value to the matcher. There are a lot of matcher functions and we can create our own too.

toBe tests for strict equality not.toBe can be used to negate a test

Red Green Refactor cycle

• You write your tests and they all fail since there's no code to make them pass.
• You then write the code to make your tests pass
• Now you can safely refactor your code and add new features.

beforeEach(), afterEach() can be used to remove redundant code

Testing async code We cannot run expect statements inside the callback function as they'll be run within the scope of our application and not the testing framework.

done() It signals to the testing framework when an async function has completed.