improve CLI tests

[pmeier]

What does this implement/fix?

Our current CLI tests are not sufficient, since our checking logic does not do what it is supposed to be doing. We only catch errors in the subprocess:

nebari/tests/test_cli.py

Lines 15 to 23 in daecbcf

	def run_cli_cmd(command: str, working_dir: typing.Union[str, Path]):
	"""Run the provided CLI command using subprocess."""
	try:
	os.chdir(working_dir)
	subprocess.call(command.split())
	except subprocess.CalledProcessError:
	return False
	return True

However, subprocess.call does not fail on exit codes > 0:

$ ls foo
"foo": No such file or directory (os error 2)
$ echo $?
2
$ python -c 'import subprocess; subprocess.call(["ls", "foo"])'
ls: cannot access 'foo': No such file or directory
$ echo $?
0

This PR uses subprocess.run instead, which is the recommended way and has the check=True flag to enable error code checking.

Put a x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features not to work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe):

Testing

• Did you test the pull request locally?
• Did you add new tests?

[iameskild]

Nice catch @pmeier! This looks good to me!