Abstract os.environ so real env doesn't interfere with tests

[pda]

Two parts of this collector need to access environment variables:

• RunEnv uses it to discover & construct run_env (CI environment details e.g. build message)
• submit() uses it to get API key/URL.

Previously we were reaching into os.environ throughout the code, and mocking it in tests like this:

with mock.patch.dict(os.environ, {"CI": "true", "BUILDKITE_ANALYTICS_TOKEN": ""}):

Now, we wrap those environment accesses behind a Mapping[str, Optional[str]] type; real code passes in os.environ, and tests pass in an arbitrary dict.

Diff best viewed with whitespace ignored, there's quite a bit of indentation change from removing the with mock…: blocks.

Related:

• Stacked on Rename RuntimeEnvironment to RunEnv #60

[Copilot]

Pull Request Overview

This PR abstracts direct os.environ accesses into injectable mappings for both the CI environment detection and API client, allowing real code to use os.environ and tests to pass controlled dictionaries.

• Introduces RunEnvBuilder to encapsulate environment‐based CI detection and removes the old detect_env function.
• Adds an API class wrapping the previous submit function, taking an env mapping in its constructor.
• Refactors tests and the pytest plugin to use the new builder and API classes instead of patching os.environ directly.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/buildkite_test_collector/collector/test_run_env.py	Refactored calls to use RunEnvBuilder instead of detect_env
tests/buildkite_test_collector/collector/test_payload.py	Changed import to only bring in timedelta
tests/buildkite_test_collector/collector/test_api.py	Swapped detect_env/submit for RunEnvBuilder/API calls
src/buildkite_test_collector/pytest_plugin/init.py	Updated plugin to build RunEnv via builder and submit via API
src/buildkite_test_collector/collector/run_env.py	Added RunEnvBuilder, removed standalone detect_env
src/buildkite_test_collector/collector/api.py	Replaced free submit with an API class

Comments suppressed due to low confidence (1)

tests/buildkite_test_collector/collector/test_payload.py:1

• The test still references datetime but it was removed from the import. Re-add datetime alongside timedelta (e.g. from datetime import datetime, timedelta).

from datetime import timedelta