test(run): isolate cloud-bootstrap tests from ambient env; add pytest dev group

[Adekunes]

What

Two small, independent test/tooling improvements to run.py's cloud-bootstrap coverage.

1. Isolate the cloud-bootstrap tests from ambient BU_* env

run.main()'s auto-bootstrap guard reads process env directly
(BROWSER_USE_API_KEY, BU_AUTOSPAWN, BU_CDP_URL, BU_CDP_WS). Any dev box
or CI runner that exports one of these leaks it into the tests:

• test_cloud_bootstrap_on_headless_server fails on a machine with an ambient
  BU_CDP_URL (e.g. a running local Chrome debug endpoint) — it makes
  _explicit_cdp_configured() return true and silently suppresses the
  start_remote_daemon call the test asserts on.
• The non-cloud tests (e.g. test_stdin_executes_code) don't mock
  start_remote_daemon, so a box exporting BU_AUTOSPAWN + a key would fire
  the real thing.

Add an autouse fixture that clears those four vars before each test, so every
test starts hermetic and only sets what it needs. Source logic is unchanged —
this only fixes the tests' env assumptions.

2. Add pytest to a dev dependency-group

Running the suite via uv run --with pytest pytest builds a fresh ephemeral
overlay venv on every cold uv cache (~2.8s) instead of the persistent project
env (~0.5s). Declaring pytest in the default dev group lets uv run pytest
resolve it from the synced project env, keeping repeat runs sub-second.
uv.lock is gitignored, so only pyproject.toml changes.

Testing

uv run pytest tests/unit -q → all green on top of current main.

🤖 Generated with Claude Code

---

Summary by cubic

Isolates cloud-bootstrap tests from ambient env vars and adds pytest to the dev dependency group to prevent flaky tests and speed up local runs.

• Bug Fixes

  • Added an autouse fixture that clears BROWSER_USE_API_KEY, BU_AUTOSPAWN, BU_CDP_URL, and BU_CDP_WS before each test.
  • Prevents false positives in the bootstrap guard and avoids triggering real start_remote_daemon on machines with BU_AUTOSPAWN or a local CDP URL.

• Dependencies

  • Added pytest>=8 to the dev group.
  • Allows uv run pytest to use the persistent project env for faster repeat runs.

^{Written for commit aa4e15a. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}