Make unit tests run in a browser

[peaBerberian]

This mega-PR rewrites unit tests so they can be run in a web browser (for now Chrome + Firefox), through webdriverio - just like our integration and memory tests.

This allows us to run unit tests in the actual environment where the RxPlayer will run and to have a common script + environment for unit, integration and memory tests, thus simplifying the project.

The main difficulty was linked to our over-reliance on vitest's doMock+importActual functions, the second which has a different behavior when run in a web browser: multiple importActual calls in the same test file won't re-evaluate that imported file. This means that doMock performed in-between importActual calls for the same file won't have an impact on that file.

This might be fixed in the future, but I wanted to see how most people succeeded to run vitest in a browser. It seems that relying on a top-level mock function is much more idiomatic, while relying on the hoisted function to also declare hoisted mocks whose implementation can change in-between tests.

Though, to ensure portability between test frameworks if we ever change it (JavaScript is like that sometimes), I try to limit reliance on that vitest-specific vi.mock/vi.hoisted concept, by prefering just mocking through only the more portable spyOn when possible.

[github-actions]

✅ Automated performance checks have passed on commit 6ed1ae612544e1b25c96bd0f5ca378d3e4ea22e5 with the base branch dev.

Details

Performance tests 1st run output

No significative change in performance for tests:

Name	Mean	Median
loading	38.72ms -> 41.00ms (corrected: -1.866ms, A/A bias: -0.415ms, z: 0.02887)	32.80ms -> 32.40ms (corrected: 0.050ms, A/A bias: 0.250ms, z: 0.61103)
seeking	145.08ms -> 120.11ms (corrected: 32.567ms, A/A bias: -7.593ms, z: 0.73612)	12.60ms -> 12.70ms (corrected: 0.150ms, A/A bias: 0.075ms, z: 0.42820)
audio-track-reload	33.90ms -> 33.82ms (corrected: 0.150ms, A/A bias: -0.078ms, z: 0.51962)	32.80ms -> 32.85ms (corrected: 0.425ms, A/A bias: -0.250ms, z: 1.51073)
loading over active content	23.82ms -> 24.06ms (corrected: -1.070ms, A/A bias: 0.824ms, z: 1.35677)	22.15ms -> 22.50ms (corrected: 0.225ms, A/A bias: 0.575ms, z: 1.35677)
large multi-period manifest	98.02ms -> 100.33ms (corrected: -3.201ms, A/A bias: 0.894ms, z: 1.31828)	91.10ms -> 93.50ms (corrected: -2.375ms, A/A bias: 0.400ms, z: 1.31828)
cold loading multithread	55.57ms -> 57.52ms (corrected: -1.821ms, A/A bias: -0.134ms, z: 0.96225)	54.40ms -> 53.10ms (corrected: 0.875ms, A/A bias: 0.150ms, z: 3.60844)
seeking multithread	90.29ms -> 105.15ms (corrected: -27.551ms, A/A bias: 12.691ms, z: 1.18357)	15.00ms -> 15.00ms (corrected: -0.225ms, A/A bias: 0.250ms, z: 1.01036)
audio-track-reload multithread	32.42ms -> 32.66ms (corrected: -0.450ms, A/A bias: 0.203ms, z: 1.42413)	31.65ms -> 31.60ms (corrected: 0.450ms, A/A bias: -0.150ms, z: 1.99186)
hot loading multithread	22.44ms -> 24.88ms (corrected: -2.305ms, A/A bias: -0.132ms, z: 0.42339)	21.50ms -> 21.60ms (corrected: -0.125ms, A/A bias: 0.050ms, z: 0.88046)

[github-actions]

✅ Automated performance checks have passed on commit 2a6a15c54d2747b86f74d0df09f2925eaecd0c72 with the base branch dev.

Details

Performance tests 1st run output

No significative change in performance for tests:

Name	Mean	Median
loading	36.33ms -> 36.87ms (corrected: 0.003ms, A/A bias: -0.545ms, z: 1.03923)	30.00ms -> 30.20ms (corrected: -0.350ms, A/A bias: 0.250ms, z: 1.68394)
seeking	152.05ms -> 176.98ms (corrected: -17.504ms, A/A bias: -7.422ms, z: 0.26943)	11.95ms -> 12.00ms (corrected: 0.425ms, A/A bias: -0.025ms, z: 0.36084)
audio-track-reload	32.36ms -> 32.59ms (corrected: -0.301ms, A/A bias: 0.076ms, z: 1.09697)	31.20ms -> 31.50ms (corrected: 0.075ms, A/A bias: -0.075ms, z: 0.12028)
loading over active content	23.14ms -> 23.25ms (corrected: -0.202ms, A/A bias: 0.091ms, z: 0.14915)	20.65ms -> 21.30ms (corrected: -1.225ms, A/A bias: 0.950ms, z: 0.14915)
large multi-period manifest	95.30ms -> 94.51ms (corrected: -0.409ms, A/A bias: 1.201ms, z: 0.19245)	85.25ms -> 86.80ms (corrected: -5.350ms, A/A bias: 6.200ms, z: 0.19245)
cold loading multithread	53.06ms -> 52.36ms (corrected: 0.653ms, A/A bias: 0.053ms, z: 1.69356)	50.60ms -> 49.90ms (corrected: 0.775ms, A/A bias: -0.050ms, z: 2.96854)
seeking multithread	121.66ms -> 106.88ms (corrected: 14.865ms, A/A bias: -0.080ms, z: 0.03849)	13.80ms -> 13.90ms (corrected: 0.050ms, A/A bias: -0.025ms, z: 0.47631)
audio-track-reload multithread	31.46ms -> 31.53ms (corrected: -0.059ms, A/A bias: -0.011ms, z: 0.07698)	30.35ms -> 30.30ms (corrected: 0.150ms, A/A bias: -0.200ms, z: 0.08660)
hot loading multithread	21.19ms -> 21.22ms (corrected: -0.058ms, A/A bias: 0.028ms, z: 0.05774)	19.70ms -> 19.70ms (corrected: -0.125ms, A/A bias: 0.150ms, z: 1.19319)