test_run_with_command_flags fails on macOS (BSD printenv doesn't support --version)

[mcpate]

Description

tests/test_cli.py::test_run_with_command_flags fails when running the test suite (via tox or pytest) on macOS.

tests/test_cli.py::test_run_with_command_flags FAILED

AssertionError: Unexpected exit code 1 (expected 0)
stdout:

stderr:
printenv: illegal option -- -
usage: printenv [name]

assert 1 == 0

Root cause

The test runs dotenv run printenv --version and asserts it exits 0, to verify that dotenv run forwards flags to the wrapped command instead of parsing them itself (added in #607 / #612).

• On Linux, printenv is GNU coreutils' version, which supports --version and exits 0.
• On macOS, printenv is the BSD version, which does not support --version at all, and exits 1 with printenv: illegal option -- -.

So the test is actually working as intended (dotenv run correctly passes --version straight through to printenv rather than swallowing it), but the assertion only holds on systems with GNU printenv.

Why this hasn't been caught in CI

.github/workflows/test.yml only runs the test matrix on ubuntu-latest and windows-latest - there's no macos-latest job, so this has never surfaced there.

CONTRIBUTING.md tells contributors to just run tox or pytest, with no mention that the suite assumes a GNU userland / Linux, so a macOS contributor following the documented steps hits this with no explanation.

Suggested fix

Replace the OS-specific sentinel command (printenv --version) with something that behaves identically across GNU/BSD/Windows, e.g. a small python -c "..." snippet that just echoes its argv, so the test only cares about flag-forwarding behavior rather than a specific external tool's flag parsing.

Environment

• macOS (Darwin), tested via tox locally
• Reproducible with plain pytest too, since it's just calling the system printenv