Jest
If file 'myCoolFile.test.js' fails, why does Jest say that every test failed?
This statement is wrong: Jest will say the file failed, BUT will also list the individual tests that passed or failed.
T/F: this test will pass with the following expect(): expect(isNull()).toBe(null)
True.
T/F: You can't use toBe() when testing for object or array equality.
True: you need to use toEqual() instead.
What is Jest?
A JavaScript testing framework with a focus on simplicity and support for large web applications.
In addition to toBe(), there are 5 other common toBe[...] functions. What are they?
DUNFT toBeDefined() toBeUndefined() toBeNull() toBeFalsy() toBeTruthy()
T/F: this test will pass with the following expect(): expect(isNull()).toBe(undefined)
False.
T/F: The following test will evaluate to true expect(someObject).toContain("propA") when someObject = {propA: "something"}.
False: this only works on arrays. HOWEVER, the following DOES evaluate to true: expect(Object.keys(someObject)).toContain("propA")
If you have a file named 'movies.js', What should the test file be?
movies.test.js
Edit this function to assert a falsehood. Don't forget to update the description and toBe()! test('adds 1 + 1 to equal 2', () =>{ expect(add(1, 1)).toBe(2); }
test('adds 1 + 1 to NOT equal 3', () =>{ expect(add(1, 1)).not.toBe(3); }
Given function 'add' which adds two numbers, write a test, and give it a description.
test('adds 1 + 1 to equal 2', () =>{ expect(add(1, 1)).toBe(2); }
If you are working with asynchronous data in Jest, what must you add in the relevant tests?
test.assertions([number of assertions])
Describe the different use cases for toBe() and toEqual().
toBe() is for primitive data types; toEqual is for referenced data (like objects and arrays).
If you wanted to check if a value was [LT, LTE, GT, GTE] which method would you call?
toBeLessThan toBeLessThanOrEqual toBeGreaterThan toBeGreaterThanOrEqual
What method is used to match Regex?
toMatch()