Mock the components of a WebExtension
npm install jest-webextension-mock    
For npm:
``bash`
npm i --save-dev jest-webextension-mock
For yarn:
`bash`
yarn add --dev jest-webextension-mock
In your package.json under the jest section add the setupFiles attribute with this module name.
`json`
"jest": {
"setupFiles": [
"jest-webextension-mock"
]
}
Alternatively you can create a new setup file and require this module.
__setups__/chrome.js`js`
require('jest-webextension-mock');
And add that file to your setupFiles:
`json`
"jest": {
"setupFiles": [
"./__setups__/chrome.js"
]
}
Use this module to check that API calls were made when expected.
`js`
describe('your function to test', () => {
it('should have called a webextension API', () => {
yourFunctionToTest();
expect(chrome.tabs.update).toHaveBeenCalled();
});
});
Check the API was called with certain parameters.
`js`
describe('your function to test', () => {
it('should have called a webextension API', () => {
yourFunctionToTest();
expect(chrome.tabs.update).toHaveBeenCalledWith({
url: 'https://example.com/'
});
});
});
And you can reset the API mocks to ensure APIs are only called when needed.
`js
beforeEach(() => {
browser.geckoProfiler.start.mockClear();
browser.geckoProfiler.stop.mockClear();
});
it('should toggle the profiler on from stopped', () => {
const store = mockStore(reducer(undefined, {}));
const expectedActions = [
{ type: 'PROFILER_START', status: 'start' },
{ type: 'PROFILER_START', status: 'done' },
];
return store.dispatch(actions.toggle()).then(() => {
expect(browser.geckoProfiler.start).toHaveBeenCalledTimes(1);
expect(store.getActions()).toEqual(expectedActions);
});
});
`
```
npm install
npm test