How to create re-usable mocks in mocha?

@cortez.connelly 

To create reusable mocks in Mocha, you can use a library like Sinon.js, which provides tools for stubbing and mocking functions. Here's an example of how you can create a reusable mock using Sinon.js in Mocha:

1. Install Sinon.js: You can install Sinon.js using npm by running the following command:

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npm install sinon

1. Create a reusable mock: You can create a mock using Sinon.js's sinon.stub function. Here's an example of a simple function that we want to mock:

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function getUser(id) {
  // This is a dummy function that fetches a user by their ID
}

To create a mock for this function in Mocha, you can do the following:

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const sinon = require('sinon');

// Create a mock for the getUser function
const getUserMock = sinon.stub().returns({ id: 1, name: 'John Doe' });

// Use the mock in your test
it('should return a user', () => {
  const user = getUserMock(1);
  // Assert that the user returned by the mock is correct
});

Now you can reuse getUserMock in multiple tests to mock the getUser function without having to redefine it every time.

1. Clean up after each test: It's important to clean up your mocks after each test to ensure that they don't affect other tests. You can use Sinon.js's sinon.restore function to restore the original function after each test:

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afterEach(() => {
  sinon.restore();
});

By following these steps, you can create reusable mocks in Mocha using Sinon.js. This allows you to easily mock functions in your tests without having to redefine them every time.