* Use .toBeCalledWith to ensure that a mock function was called with * specific arguments.

* Using exact equality with floating point numbers is a bad idea. Rounding * means that intuitive things fail.

* Use .toBeDefined to check that a variable is not undefined.

* To compare floating point numbers, you can use toBeGreaterThan.

* To compare floating point numbers, you can use toBeGreaterThanOrEqual.

* To compare floating point numbers, you can use toBeLessThan.

* To compare floating point numbers, you can use toBeLessThanOrEqual.

* .toBeNull() is the same as .toBe(null) but the error messages are a bit * nicer.

* Use .toContain when you want to check that an item is in a list. For * testing the items in the list, this uses ===, a strict equality check.

* Use .toContainEqual when you want to check that an item is in a list. For * testing the items in the list, this matcher recursively checks the

* Use .toHaveBeenLastCalledWith to ensure that a mock function was last called * with specific arguments.

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* Check that an object has a .length property and it is set to a certain * numeric value.

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* Use .toMatch to check that a string matches a regular expression or string.

* Use .toMatchObject to check that a javascript object matches a subset of the properties of an object.

* This ensures that an Object matches the most recent snapshot.

* Use .toStrictEqual to check that a javascript object matches a subset of the properties of an object.

* Use .toThrowErrorMatchingSnapshot to test that a function throws a error * matching the most recent snapshot when it is called.