Global values

Global Values (🏁 solution)

As it often does, the test begins from the setup. In this case, the setup includes the introduction of both beforeAll and afterAll hooks to the test suite.

beforeAll(() => {
  vi.stubGlobal('location', new URL('http://localhost/base/'))
})

In the beforeAll() hook, I'm using the vi.stubGlobal() function to replace the value of the global property location with a mocked URL instance. I intentionally provide a mock URL with a path (/base/) to make sure that the toAbsoluteUrl() function handles relative paths correctly.

And, of course, I am making sure that the global location object is unstubbed by calling vi.unstubAllGlobals() in the afterAll() hook.

afterAll(() => {
  vi.unstubAllGlobals()
})

Now, to the test cases!

The first one is about the scenario where an absolute URL provided to the tested function is returned as-is. That's precisely what I will do:

test('returns an absolute url as-is', () => {
  expect(toAbsoluteUrl('https://example.com/')).toBe('https://example.com/')
})

The next scenario involves handling relative URLs that only include paths. In itself, it can be split into two use cases:

When an absolute path is provided (e.g. /abc);
When a relative path is provided (e.g. ./abc; notice the dot .).

While both being based on the mocked location.href, these two scenarios will yield different URLs, which I make sure to cover in tests:

test('resolves a relative url against the current location', () => {
  expect(toAbsoluteUrl('/resource')).toBe('http://localhost/resource')
  expect(toAbsoluteUrl('./resource')).toBe('http://localhost/base/resource')
})

By mocking the value of location in this test suite, I have isolated it. Everything that affects the test results of the toAbsoluteUrl() function is now contained within this single test file.

04. Globals/02. Global values (🏁 solution)

Global values