{Role} fix test fail when running in serial due to buggy way to swtich tempory folder back

[haroldrandom]

Description
When running these 2 tests in serial:

1. test_role.py::RoleAssignmentScenarioTest::test_role_assignment_handle_conflicted_assignments
2. test_role.py::RoleAssignmentScenarioTest::test_role_assignment_mgmt_grp
   The second one will fail on Linux but succeed on Windows.

Why failed on Linux?
At the beginning, the 1st test would chdir to a temporary dir.

azure-cli/src/azure-cli/azure/cli/command_modules/role/tests/latest/test_role.py

Lines 351 to 354 in 280692d

	base_dir = os.curdir
	try:
	temp_dir = self.create_temp_dir()
	os.chdir(temp_dir)

and at the end the of test, it would try to switch back but actually it didn't because the basr_dir is a relative path. So, the original directory is lost and the test procedure would stay at the temporary directory.

azure-cli/src/azure-cli/azure/cli/command_modules/role/tests/latest/test_role.py

Lines 369 to 372 in 280692d

	finally:
	self.cmd('configure --default group="" --scope local')
	os.chdir(os.path.basename(base_dir))
	self.cmd('ad user delete --upn-or-object-id {upn}')

However, during the creation of tempory directory, it will register a callback to clean this folder away after the test is done.

    # IntegrationTestBase from base.py (azure_devtools)
    def create_temp_dir(self):
        """
        Create a temporary directory for testing. The test harness will delete the directory during tearing down.
        """
        temp_dir = tempfile.mkdtemp()
        self.addCleanup(lambda: shutil.rmtree(temp_dir, ignore_errors=True))

        return temp_dir

So, when the second test starts, it's in a non-existing directory, and the intialization of CLI instannce would fail due to LocalContext object require reading a file from current dir:

======================================================================================================================================== ERRORS ========================================================================================================================================
______________________________________________________________________________________________________ ERROR at setup of RoleAssignmentScenarioTest.test_role_assignment_mgmt_grp ______________________________________________________________________________________________________

self = <[AttributeError("'RoleAssignmentScenarioTest' object has no attribute '_testMethodName'",) raised in repr()] RoleAssignmentScenarioTest object at 0x7fa0ac645f60>, method_name = 'test_role_assignment_mgmt_grp', config_file = None, recording_name = None
recording_processors = None, replay_processors = None, recording_patches = None, replay_patches = None

    def __init__(self, method_name, config_file=None, recording_name=None,
                 recording_processors=None, replay_processors=None, recording_patches=None, replay_patches=None):
>       self.cli_ctx = get_dummy_cli()

/home/harold/Microsoft/azure-cli/src/azure-cli-testsdk/azure/cli/testsdk/base.py:82: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
/home/harold/Microsoft/azure-cli/src/azure-cli-testsdk/azure/cli/testsdk/reverse_dependency.py:14: in get_dummy_cli
    return getattr(mod, 'DummyCli')(*args, **kwargs)
/home/harold/Microsoft/azure-cli/src/azure-cli-core/azure/cli/core/mock.py:34: in __init__
    invocation_cls=AzCliCommandInvoker)
/home/harold/Microsoft/azure-cli/src/azure-cli-core/azure/cli/core/__init__.py:73: in __init__
    dir_name=os.path.basename(self.config.config_dir), file_name='local_context'
/home/harold/Microsoft/azure-cli/src/azure-cli-core/azure/cli/core/local_context.py:27: in __init__
    self._load_local_context_file()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <azure.cli.core.local_context.AzCLILocalContext object at 0x7fa0ad3ad198>

    def _load_local_context_file(self):
>       current_dir = os.getcwd()
E       FileNotFoundError: [Errno 2] No such file or directory

/home/harold/Microsoft/azure-cli/src/azure-cli-core/azure/cli/core/local_context.py:30: FileNotFoundError

Why succeeded on Windows
The removal temporary dir is ignoring the permission error

shutil.rmtree(temp_dir, ignore_errors=True)

If set ignore=False, you will see:

So, the deletion wouldn't succeed and the second test would stuck in that temporary folder and succeed just lucky.

Testing Guide
Before fix, run via

pytest -x -v -p no:warnings --log-level=WARN \
src/azure-cli/azure/cli/command_modules/role/tests/latest/test_role.py::RoleAssignmentScenarioTest::test_role_assignment_handle_conflicted_assignments \
src/azure-cli/azure/cli/command_modules/role/tests/latest/test_role.py::RoleAssignmentScenarioTest::test_role_assignment_mgmt_grp

History Notes

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[jiasli]

FYI, the success on Windows is similar to microsoft/knack#177. Have to admit Windows is smarter on this.