Writing test cases in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of writing test cases in Node.js?

Test cases help check if your code works correctly by running small checks automatically. They catch errors early and make sure changes don’t break existing features.

beginner

What does a typical test case include?

A test case usually has three parts: setup (prepare data or state), execution (run the code), and assertion (check if the result matches what you expect).

beginner

In Node.js testing, what is an assertion?

An assertion is a statement that checks if a value or result is what you expect. If it’s not, the test fails and tells you there’s a problem.

intermediate

Why use a testing framework like Mocha or Jest in Node.js?

Testing frameworks give you tools to write, organize, and run tests easily. They handle running tests, showing results clearly, and help write assertions.

intermediate

What is a 'mock' in testing?

A mock is a fake version of a function or module used in tests to simulate behavior without running real code. It helps test parts of code in isolation.

Which part of a test case checks if the output is correct?

A Assertion

B Setup

C Execution

D Cleanup

The assertion checks if the output matches the expected result.

What is the benefit of using a testing framework like Jest?

A It helps write and run tests easily

B It makes your code run faster

C It automatically fixes bugs

D It replaces the need for writing code

Testing frameworks provide tools to write, organize, and run tests efficiently.

What does a 'mock' do in a test?

A Generates random data

B Deletes test files automatically

C Runs the entire application

D Simulates a part of code to isolate testing

Mocks simulate parts of code so you can test components without running real dependencies.

Which of these is NOT a typical part of a test case?

A Setup

B Assertion

C Compilation

D Execution

Compilation is not part of writing test cases; it relates to building code.

Why write test cases before fixing bugs?

A To make the code slower

B To confirm the bug exists and prevent future errors

C To avoid writing code

D To delete old files

Writing tests first helps confirm bugs and ensures fixes don’t break other parts.

Explain the three main parts of a test case and why each is important.

Think about preparing data, running code, and checking results.

Describe how using mocks can help when writing test cases in Node.js.

Imagine replacing a real part with a fake one to test only what you want.