This is a great way to wait until a mocked API call is done.

Nifty!

presumably when we expand test coverage in our other areas of the repo we'll need to mock this out in those files to override the pathname?

That's right. My assumption is that most of the tests will be fine with this path, but if they need to use a different one, they can just do this:

jest.mock('react-router-dom', () => {
  const originalModule = jest.requireActual('react-router-dom');
  return {
    ...originalModule,
    useHistory: jest.fn(),
    useLocation: jest.fn(() => {
      return {
        pathname: '/feature-z/page-1',
      };
    }),
  }
});

Is it possible for us to test what the URL will go to here instead of just checking the link text? It'd help to ensure that changes made to the URL but not the text don't pass through our test cases.

Great point, will add an assertion for a URL.

I've checked the code and we don't render a link, but open a new tab via an onClick event on a div element:
onClick={() => global.platform.openTab({ url: blockExplorerUrl })}

I will be testing events in following PRs, so I would prefer to do it there.

I am assuming this snapshot exists just to confirm that the loading-swaps-quotes-stories-metadata file isn't touched, or if it is that it is intentional?

Exactly. If there would be any change in loading-swaps-quotes-stories-metadata.js, a test would fail with an outdated snapshot. It's just a double-check that someone didn't accidentally modify it + it was showing 0% test coverage, which was lowering our overall coverage.

Why did this get turned off?

Great question! That's because I used module.exports in the link below: https://github.com/MetaMask/metamask-extension/pull/10934/files#diff-8fd96322fc664541ebc0326e3c5963e55db825809abb977c6ffad8be7555cbd1R7
After which I started getting these errors:

I will give it little more time to use export instead of module.exports when re-exporting imported things. Then we hopefully wouldn't need to turn import/named off for tests.

So, I've changed it to export only:

export { createSwapsMockStore } from './mock-store';
export { renderWithProvider } from './rendering';
export { setBackgroundConnection } from './background';
export * as MOCKS from './mocks';
export * as CONSTANTS from './constants';

But even while tests are green, I'm getting the same ESLint issue when re-exporting:

That's why I would prefer to keep 'import/named': 'off',, just for tests.

looks legit. import-js/eslint-plugin-import#1998

Nice find!

why the removal of the collectCoverageFrom flag

I've moved it to jest.config.js: https://github.com/MetaMask/metamask-extension/pull/10934/files/581c2fb2962fbb64d0772f57c451c89d3e1dd12c#diff-1e058ca1442e46581b13571fb8d261f9e1f5657e26c96634d4c1072f0f0347f1R4