Test your React Application with Jest and React Testing Library

Evaluated skills

Test your React app with Jest and React Testing Library

Question 1
Which of these statements are false?
Careful, there are several correct answers.
- If the name of your test ends with .test.js , you can put your file wherever you like in /src .
- Unit testing is the type of test that takes the longest to write.
- Tests provide security when modifying a codebase.
- You can call your test files whatever you like, as long as you put them in a _test_ folder.
- Continuous integration is a solution that triggers testing while you write your code.

Question 2

You’ve written a timesThree function that multiplies the number passed as an argument by 3.

export function timesThree(numberToMultiply) {
 return numberToMultiply * 3
}

You create an index.test.js file. Which code snippets will test this function for you?

Careful, there are several correct answers.

it('should multiply by 3', () => {
   const expected = 6
   expect(timesThree(2)).toBe(expected)
 })

describe('The timesThree function', () => {
 test('should multiply by 3', () => {
   const expected = 6
   expect(timesThree(2)).toBe(expected)
 })
})

describe('The timesThree function', () => {
 test(() => {
   const expected = 6
   expect(timesThree(2)).toBe(expected)
 })
})

test('should multiply by 3', () => {
   expect(timesThree(2)) === 6
 })

Question 3
Complete the phrase with the correct answers: Code coverage…
Careful, there are several correct answers.
- should be 100 % for a modification to be considered reliable.
- is a good indicator of the lines of code that are covered by tests.
- is launched with the command yarn test -- --coverage .
- needs to be installed with yarn add --dev jest/coverage .

Test your React Application with Jest and React Testing Library

Evaluated skills

Question 1

Question 2

Question 3