test_hook_writes_to_stderr failure "/bin/sh command not found"

[zaro0508]

Subject of the issue

FAILED tests/test_hooks/test_cmd.py::test_hook_writes_to_stderr - AssertionError: assert '/bin/sh: mis...and not found' == '/bin/sh: 1: ...nd: not found' when I run Sceptre unit test.

Your environment

• Sceptre v 4.3.0
• Python v 3.9
• MAC OSX Sonoma 14.0

Steps to reproduce

1. poetry install
2. pyenv shell 3.9
3. ➜ python -V
   Python 3.9.7
4. ➜ /bin/sh --version
   GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin23)
   Copyright (C) 2007 Free Software Foundation, Inc.
5. poetry run pytest

Expected behaviour

All tests pass

Actual behaviour

1 test failure..

stack = sceptre.stack.Stack(name='stack1', project_code=project1, template_handler_config={'template': 'path.yaml'}, region=re...ions=[], on_failure=None, disable_rollback=False, stack_timeout=0, stack_group_config={}, ignore=False, obsolete=False)
capfd = <_pytest.capture.CaptureFixture object at 0x1102a76d0>

    def test_hook_writes_to_stderr(stack, capfd):
        with pytest.raises(Exception):
            Cmd("missing_command", stack).run()
        cap = capfd.readouterr()
        assert cap.out.strip() == ""
>       assert cap.err.strip() == "/bin/sh: 1: missing_command: not found"
E       AssertionError: assert '/bin/sh: mis...and not found' == '/bin/sh: 1: ...nd: not found'
E         - /bin/sh: 1: missing_command: not found
E         ?         ---
E         + /bin/sh: missing_command: command not found
E         ?                           ++++++++

tests/test_hooks/test_cmd.py:150: AssertionError

[zaro0508]

This test was added in PR #1372, do you know anything about it @iainelder ?

[iainelder]

Yes, I added it. Not sure why it would fail. I'll take a look tomorrow!

[iainelder]

To follow your repro I need to install pyenv. I'll figure out how to do that this week.

What do you see when you skip the pyenv command and run poetry run tox -e py39?

For me, all the tests pass in tox's py39 environment.

[iainelder]

Your /bin/sh points to Bash. (It looks like your system is macOS.)

My /bin/sh points to Dash. My system is Ubuntu 20.

The shells write different error messages when they can't find the command.

• Bash: /bin/bash: missing_command: command not found
• Dash: /bin/dash: 1: missing_command: not found

The test expects /bin/sh to write Dash's error message.

Your /bin/sh writes Bash's error message, and so the test fails.

---

All I want to test here is that the hook writes to the standard error stream.

I think I should rewrite it so that it no longer depends on system-defined side effects of a missing command.

A simpler test would just echo text to the standard error stream and check that the same text comes out.