Implement wrangler dev --(experimental-)local E2E tests

[mrbbot]

What this PR solves / how to test:

Wrangler has lots of tests, but none that simulate the full user flow for common operations (npm install, wrangler dev, wrangler publish). This PR adds end-to-end testing for wrangler dev --(experimental-)local.

Importantly, these E2E tests:

• Install wrangler using npm as a user would, meaning we don't have access to wrangler's devDependencies in tests
• Run wrangler with a pseudo-TTY, meaning we can run wrangler with stdin in "raw" mode, and test interactive elements like hotkeys
• Determine when wrangler is listening based on stdout as a user would

The E2E tests in this PR (would) have caught the following issues:

• 🐛 BUG: Local server not starting #2334 (fixed in Fix wrangler dev --local and its lazy imports of @miniflare/tre #2339)
• 🐛 BUG: wrangler dev --experimental-local requires login #2383 (fixed in Remove login requirement from --experimental-local #2393)
• 🐛 BUG: wrangler dev --experimental-local doesn't cleanly shut down the server #2387 (fixed in Allow --experimental-local to cleanly exit on x/CTRL-C #2400)
• ReferenceError: fetch is not defined when using --experimental-local mode on Node 16, and corresponding tsconfg issues (fixed as part of Untangle wrangler types 🙈 #2377)
• If the --local mode miniflare-cli script throws outside of user code, wrangler hangs on Waiting for the debugger to disconnect... and doesn't log the error (not yet fixed)
• If --port=0 is used with --local mode, a new port will be used whenever the user updates their script (not yet fixed)
• Miniflare 3 was missing the lib directory from its npm distribution (fixed in @miniflare/tre@3.0.0-next.10)
• events.once leaks signal listener nodejs/node#43337 😅

We'll add E2E tests for remote wrangler dev and wrangler publish in the new year.

To try out the E2E tests, run npm build in the repository root, then change into the e2e directory, and run npm test.

Associated docs issues/PR:

N/A

Author has included the following, where applicable:

• Tests 😄
• Changeset (no user facing changes)

Reviewer has performed the following, where applicable:

• Checked for inclusion of relevant tests
• Checked for inclusion of a relevant changeset
• Checked for creation of associated docs updates
• Manually pulled down the changes and spot-tested

Ref #2351

[changeset-bot]

⚠️ No Changeset found

Latest commit: f6c55ce

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[github-actions]

A wrangler prerelease is available for testing. You can install this latest build in your project with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/runs/3937933656/npm-package-wrangler-2365

You can reference the automatically updated head of this PR with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/prs/2365/npm-package-wrangler-2365

Or you can use npx with this latest build directly:

npx https://prerelease-registry.devprod.cloudflare.dev/runs/3937933656/npm-package-wrangler-2365 dev path/to/script.js

Additional artifacts:

npm install https://prerelease-registry.devprod.cloudflare.dev/runs/3937933656/npm-package-cloudflare-pages-shared-2365

[codecov]

Codecov Report

Merging #2365 (f6c55ce) into main (4db768f) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #2365      +/-   ##
==========================================
- Coverage   72.99%   72.97%   -0.02%     
==========================================
  Files         156      156              
  Lines        9745     9747       +2     
  Branches     2568     2568              
==========================================
  Hits         7113     7113              
- Misses       2632     2634       +2     

Impacted Files	Coverage Δ
packages/wrangler/src/dev/local.tsx	21.97% <0.00%> (-0.17%)	⬇️

[penalosa]

Very excited for this! Couple small comments (mostly clarification questions)

[penalosa]

Are both of these necessary?

[mrbbot]

We need some way of knowing if the process has already exited in cleanupSpawnedProcesses, and you can't inspect Promise state without awaiting it. We could just have a boolean exited flag, but this seemed like it could be useful in tests.

[penalosa]

I feel like there should be a seed-like helper function for updating files

[mrbbot]

Hmmm, seed could return something like an instance of a RootedFileSystem<FileName extends string> class, with read/write/delete/replace methods. But I don't think we'll be replacing files too often for this to be needed? 🤷

[JacobMGEvans]

I have no major callouts on this PR. No nits either. Thededent() is clever

My approval is tentative to @penalosa comments being resolved & checks fixed

[warn] e2e/package.json
[warn] Code style issues found in the above file. Forgot to run Prettier?

Edit: We should look into this framework to use it or if there is anything we can use from it https://github.com/node-modules/clet

[penalosa]

LGTM!

[Cherry]

Would be awesome to see this merged 👀

[Cherry]

Hoping this lands in v3 soon 👀

[mrbbot]

Closing in favour of #3344