Writing Unit Tests with Mocha JS

1. How do you write unit test cases with mocha?
2. How do you do the Mocha unit test?
3. How do I run a specific test file in mocha?
4. How do I run a mocha test in terminal?
5. Which is better mocha or jest?
6. What is done in mocha?
7. What is Mocha NPM?
8. Does Mocha run tests in parallel?
9. What is the difference between mocha and Jasmine?
10. How do you skip the mocha test?
11. How do I run a specific test file?
12. How do you debug a mocha test?

How do you write unit test cases with mocha?

With Node installed, open up a terminal or command line in your project's directory.

1. If you want to test code in the browser, run npm install mocha chai --save-dev.
2. If you want to test Node.js code, in addition to the above, run npm install -g mocha.

How do you do the Mocha unit test?

Using test hooks with Mocha. js

1. before() runs once before the first test case in the block.
2. beforeEach() runs before each test case.
3. afterEach() runs after each test case.
4. after() runs once after the last test case in the block.

How do I run a specific test file in mocha?

Run a Single Test File

Using the mocha cli, you can easily specify an exact or wildcarded pattern that you want to run. This is accomplished with the grep option when running the mocha command. The spec must have some describe or it that matches the grep pattern, as in: describe('api', _ => // ... )

How do I run a mocha test in terminal?

Testing with mocha

1. Add mocha and should. js to your package. ...
2. run npm install to update.
3. Create a mocha. opts file to store common config settings. ...
4. Add a test command to your packages. json file. ...
5. Create a test case. ...
6. Open a new terminal window.
7. Run mocha test runner npm test. ...
8. Keep the terminal window open.

Which is better mocha or jest?

Jest is an open source testing framework developed by Facebook. Built into the popular create-react-app package, is faster and smoother to write idiomatic JavaScript tests. ... Mocha provides developers with a base test framework, with options such as assertion, mocking, and spy libraries.

What is done in mocha?

The first code snippet with the before hook returns a promise and calls done . In Mocha 3. x and over, it will result in this error: Error: Resolution method is overspecified. ... In your 2nd snippet, you have the done argument and return a promise but Mocha will still wait for done to be called and will timeout.

What is Mocha NPM?

Mocha is a testing library for Node. js, created to be a simple, extensible, and fast. It's used for unit and integration testing, and it's a great candidate for BDD (Behavior Driven Development). ... In addition, we will create a web server that exposes the above converter and demonstrates how to test asynchronous code.

Does Mocha run tests in parallel?

Mocha does not run individual tests in parallel.

That means if you hand Mocha a single, lonely test file, it will spawn a single worker process, and that worker process will run the file. If you only have one test file, you'll be penalized for using parallel mode.

What is the difference between mocha and Jasmine?

In conclusion, the Jasmine framework has almost everything built into it including assertions/expectations and test double utilities (which come in the form of spies). ... Mocha on the other hand includes a test runner and an API for setting up your test suite but does not include assertion and test double utilities.

How do you skip the mocha test?

You can skip tests by placing an x in front of the describe or it block, or placing a . skip after it. describe('feature 1', function() ); describe.

How do I run a specific test file?

You can open your test file in Visual Studio Code and click on one of those options. If you are running npm >= 5.2. 0 and you have installed Jest locally as a devDependencies with npm i -d jest , you can run Jest on a particular file by doing npx jest /path/to/your/spec.

How do you debug a mocha test?

How to debug Mocha tests running in Node using Chrome DevTools inspector.

1. Break at the start of the Node process. ...
2. When starting the tests it pauses the execution and outputs the following message. ...
3. Open in Chrome special url chrome://inspect which shows that there is a "remote target" available to connect.