How to unit test node.js functions with mocha?

@rollin 

To unit test Node.js functions using Mocha, you can follow these steps:

1. Install Mocha and any other necessary testing libraries:

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npm install mocha chai

1. Create a test file for your Node.js functions. For example, if you have a function in a module called example.js, create a example.test.js file in the same directory.
2. In your test file, import the necessary modules and functions:

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const assert = require('chai').assert;
const example = require('./example');

1. Write test cases using Mocha's describe and it functions. For example:

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describe('Example', function() {
  it('should return the sum of two numbers', function() {
    assert.equal(example.add(1, 2), 3);
  });

  it('should return the difference of two numbers', function() {
    assert.equal(example.subtract(5, 3), 2);
  });
});

1. Run your tests by running Mocha in the terminal:

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./node_modules/.bin/mocha

Alternatively, you can add a script to your package.json file to run the tests:

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"scripts": {
  "test": "mocha"
}

Then you can run your tests using:

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npm test

1. Analyze the output of Mocha to see if your tests passed or failed.

By following these steps, you can effectively unit test your Node.js functions using Mocha.