Migrate Testing from Jest to Vitest (#27)

[ThomasKaar]

Migrate Testing from Jest to Vitest (#27)

♻️ Current situation & Problem

As described in #27, vitest is a more modern and faster testing framework.

⚙️ Release Notes

• Added vitest
• Removed jest

📚 Documentation

This Pull Request migrates Jest to Vitest according to the official vitest documentation and the Next.js testing guide.
The packages:

• @types/jest
• jest
• jest-environment-jsdom
• ts-jest

have been removed

✅ Testing

Before

$ npm run test
...
 PASS  app/page.test.tsx
  Home Component
    ✓ renders the Stanford Biodesign Digital Health Next.js Template heading (92 ms)
    ✓ renders the Stanford Biodesign Logo (6 ms)

-------------------------------|---------|----------|---------|---------|-------------------
File                           | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
-------------------------------|---------|----------|---------|---------|-------------------
All files                      |     100 |       75 |     100 |     100 |                   
 app                           |     100 |       75 |     100 |     100 |                   
  page.tsx                     |     100 |       75 |     100 |     100 | 19                
 packages/example-package/dist |     100 |      100 |     100 |     100 |                   
  index.js                     |     100 |      100 |     100 |     100 |                   
-------------------------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        3.294 s
Ran all test suites.

After

$ npm run test
...
 ✓ app/page.test.tsx (2)
   ✓ Home Component (2)
     ✓ renders the Stanford Biodesign Digital Health Next.js Template heading
     ✓ renders the Stanford Biodesign Logo

 Test Files  1 passed (1)
      Tests  2 passed (2)
   Start at  21:47:52
   Duration  1.77s (transform 86ms, setup 0ms, collect 385ms, tests 103ms, environment 683ms, prepare 100ms)

 % Coverage report from v8
------------------------------|---------|----------|---------|---------|-------------------
File                          | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
------------------------------|---------|----------|---------|---------|-------------------
All files                     |   74.46 |    66.66 |   66.66 |   74.46 |                   
 app                          |      60 |       50 |      50 |      60 |                   
  layout.tsx                  |       0 |        0 |       0 |       0 | 1-28              
  page.tsx                    |     100 |      100 |     100 |     100 |                   
 packages/example-package/src |     100 |      100 |     100 |     100 |                   
  index.ts                    |     100 |      100 |     100 |     100 |                   
------------------------------|---------|----------|---------|---------|-------------------

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[PSchmiedmayer]

@ThomasKaar Thank you for the addition and taking a look at the issue!
I have requested a detailed review from @arkadiuszbachorski.

Looking at the PR at a high level, it seems like the coverage report you detail above is also including js files and reports a 0% test coverage for the TS files wich might not be correct.
It might make sense to take a look at some of the chances and mechanisms we made in https://github.com/StanfordBDHG/ENGAGE-HF-Web-Frontend which seems to properly report some TS test coverage despite some elements that we could improve there as well.

[ThomasKaar]

Thanks for the brief review!

I reduced the scope of the coverage analysis similar to https://github.com/StanfordBDHG/ENGAGE-HF-Web-Frontend while also including js files with sourceMap enabled so the ts-file can be properly mapped to the js-file in the coverage analysis (I updated the test plan accordingly).

Moreover, I also added licensing information to the newly added vitest.config.mts and ran npm run lint:ci locally to ensure it is working properly

[PSchmiedmayer]

Thank you @ThomasKaar; greatly appreciated!
Just started the builds and I can sync with @arkadiuszbachorski about the next steps 👍