Make sure that 'tox -erust' fails on bad RC.

[kevinhartman]

Summary

Previously, a non-zero exit code from the subprocess would not fail the tox run like we'd expect.

[qiskit-bot]

One or more of the following people are relevant to this code:

• @Qiskit/terra-core

[coveralls]

Pull Request Test Coverage Report for Build 13035694187

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 9 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.001%) to 88.931%

---

Files with Coverage Reduction	New Missed Lines	%
crates/accelerate/src/unitary_synthesis.rs	1	92.97%
crates/qasm2/src/lex.rs	2	92.98%
crates/qasm2/src/parse.rs	6	96.68%

Totals
Change from base Build 13010967771:	-0.001%
Covered Lines:	79678
Relevant Lines:	89595

---

💛 - Coveralls

[mtreinish]

LGTM, just left a small comment inline. It doesn't really matter in this context though.

[mtreinish]

Not that it particularly matters in this context. But what I normally do is:

Suggested change

	subprocess.run(["cargo", "test", "--no-default-features"]).check_returncode()'
	subprocess.run(["cargo", "test", "--no-default-features"], check=True)'

[jakelishman]

I think pylint has a lint against failing to check the return code of subprocess.run - it might be a motivation to move this inline script into a proper file in the tools directory so it's subject to lint?

[jakelishman]

It does: https://pylint.readthedocs.io/en/latest/user_guide/messages/warning/subprocess-run-check.html

[kevinhartman]

Seems like a good idea, and should let us use the same script from tox and CI.

Done in 663eaa8.

[mtreinish]

This LGTM for the most part. I like having the script in a dedicated file now. Just one question/suggestion inline.

[mtreinish]

Is there a reason to not just do?:

Suggested change

	os.environ["LD_LIBRARY_PATH"] = os.pathsep.join(
	filter(None, [sysconfig.get_config_var("LIBDIR"), os.getenv("LD_LIBRARY_PATH")])
	)
	os.environ["LD_LIBRARY_PATH"] = os.pathsep.join([
	sysconfig.get_config_var("LIBDIR"),
	os.getenv("LD_LIBRARY_PATH")
	])

I've always found the filter(None, ...) pattern a bit odd when you can just use a generator expression.

[kevinhartman]

The reason I did that was to filter out None in the case that "LD_LIBRARY_PATH" isn't actually set to anything. I can do something different if you prefer!