azdev test --debug doesn't work

--debug doesn't print API call information as expected.

(env) E:\Microsoft\AzureCLI\azure-cli>azdev test test_functionapp_access_restriction_add --live --debug
Command arguments: ['test', 'test_functionapp_access_restriction_add', '--live', '--debug']
Event: Cli.PreExecute []
Event: CommandParser.OnGlobalArgumentsCreate [<function CLILogging.on_global_arguments at 0x0000023F4657E8B8>, <function OutputProducer.on_global_arguments at 0x0000023F468E1AF8>, <function CLIQuery.on_global_arguments at 0
x0000023F4690E438>]
Event: CommandInvoker.OnPreCommandTableCreate []
Event: CommandLoader.OnLoadCommandTable []
Event: CommandLoader.OnLoadArguments []
Event: CommandInvoker.OnPostCommandTableCreate []
Event: CommandInvoker.OnCommandTableLoaded []
Event: CommandInvoker.OnPreParseArgs []
Event: CommandInvoker.OnPostParseArgs [<function OutputProducer.handle_output_argument at 0x0000023F468E1B88>, <function CLIQuery.handle_query_parameter at 0x0000023F4690E4C8>]

=============
| Run Tests |
=============

The tests are set to run against current profile latest.

test index found: C:\Users\zuh\.azdev\env_config\Microsoft\AzureCLI\azure-cli\env\test_index\latest.json

TESTS: test_functionapp_access_restriction_add

RUNNING TESTS LIVE
Running: python -m pytest -p no:warnings --no-print-logs --junit-xml C:\Users\zuh\.azdev\env_config\Microsoft\AzureCLI\azure-cli\env\test_results.xml e:\microsoft\azurecli\azure-cli\src\azure-cli\azure\cli\command_modules\a
ppservice\tests\latest\test_functionapp_access_restriction_commands.py::FunctionAppAccessRestrictionScenarioTest::test_functionapp_access_restriction_add -n auto
==================================================================================================== test session starts =====================================================================================================
platform win32 -- Python 3.7.4, pytest-4.4.2, py-1.8.0, pluggy-0.13.0
rootdir: e:\microsoft\azurecli\azure-cli\src\azure-cli
plugins: forked-1.1.1, xdist-1.30.0
gw0 [1] / gw1 [1] / gw2 [1] / gw3 [1] / gw4 [1] / gw5 [1] / gw6 [1] / gw7 [1]
F                                                                                                                                                                                                                       [100%]
========================================================================================================== FAILURES ==========================================================================================================
______________________________________________________________________ FunctionAppAccessRestrictionScenarioTest.test_functionapp_access_restriction_add ______________________________________________________________________
[gw0] win32 -- Python 3.7.4 E:\Microsoft\AzureCLI\azure-cli\env\Scripts\python.exe

self = <azure.cli.command_modules.appservice.tests.latest.test_functionapp_access_restriction_commands.FunctionAppAccessRestrictionScenarioTest testMethod=test_functionapp_access_restriction_add>
resource_group = 'clitest.rgtnivwr7ja4rqjex4qeptlkahjqwdmj3gsliszba2btnx47dnvjulptec6oj5uzps6', location = 'westus'

    @ResourceGroupPreparer(parameter_name_for_location='location')
    @StorageAccountPreparer()
    def test_functionapp_access_restriction_add(self, resource_group, location):
        self.kwargs.update({
            'app_name': self.create_random_name(prefix='cli-funcapp-nwr', length=24),
            'loc': location
        })
    
        self.cmd('functionapp create -g {rg} -n {app_name} --consumption-plan-location {loc} -s {sa}', checks=[
            JMESPathCheck('state', 'Running')
        ])
    
        self.cmd('functionapp config access-restriction add -g {rg} -n {app_name} --rule-name developers --action Allow --ip-address 130.220.0.0/27 --priority 200', checks=[
            JMESPathCheck('length(@)', 2),
            JMESPathCheck('[0].name', 'developers'),
            JMESPathCheck('[0].action', 'Allow'),
            JMESPathCheck('[1].name', 'Deny all'),
>           JMESPathCheck('[1].action', 'Deny')
        ])

src\azure-cli\azure\cli\command_modules\appservice\tests\latest\test_functionapp_access_restriction_commands.py:96:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
src\azure-cli-testsdk\azure\cli\testsdk\base.py:161: in cmd
    return execute(self.cli_ctx, command, expect_failure=expect_failure).assert_with_checks(checks)
src\azure-cli-testsdk\azure\cli\testsdk\base.py:227: in assert_with_checks
    c(self)
src\azure-cli-testsdk\azure\cli\testsdk\checkers.py:18: in __call__
    json_value = execution_result.get_output_in_json()
src\azure-cli-testsdk\azure\cli\testsdk\base.py:233: in get_output_in_json
    self.json_value = json.loads(self.output)
C:\Users\zuh\AppData\Local\Programs\Python\Python37\lib\json\__init__.py:348: in loads
    return _default_decoder.decode(s)
C:\Users\zuh\AppData\Local\Programs\Python\Python37\lib\json\decoder.py:337: in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <json.decoder.JSONDecoder object at 0x00000241B86725C8>, s = '', idx = 0

    def raw_decode(self, s, idx=0):
        """Decode a JSON document from ``s`` (a ``str`` beginning with
        a JSON document) and return a 2-tuple of the Python
        representation and the index in ``s`` where the document ended.
    
        This can be used to decode a JSON document from a string that may
        have extraneous data at the end.
    
        """
        try:
            obj, end = self.scan_once(s, idx)
        except StopIteration as err:
>           raise JSONDecodeError("Expecting value", s, err.value) from None
E           json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

C:\Users\zuh\AppData\Local\Programs\Python\Python37\lib\json\decoder.py:355: JSONDecodeError
---------------------------------------------------------------------------------------------------- Captured stderr call ----------------------------------------------------------------------------------------------------
WARNING: The behavior of this command has been altered by the following extension: storage-preview
WARNING: The behavior of this command has been altered by the following extension: storage-preview
WARNING: Application Insights "cli-funcapp-nwrcpyerwhzl" was created for this Function App. You can visit https://portal.azure.com/#resource/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590/resourceGroups/clitest.rgtnivwr
7ja4rqjex4qeptlkahjqwdmj3gsliszba2btnx47dnvjulptec6oj5uzps6/providers/microsoft.insights/components/cli-funcapp-nwrcpyerwhzl/overview to view your Application Insights component
This command group is in preview. It may be changed/removed in a future release.
------------------------------------------------------------ generated xml file: C:\Users\zuh\.azdev\env_config\Microsoft\AzureCLI\azure-cli\env\test_results.xml ------------------------------------------------------------
================================================================================================= 1 failed in 113.28 seconds =================================================================================================

 Results
=========

Time: 113.230 sec       Tests: 1        Skipped: None   Failures: 1     Errors: 0

 FAILURES
==========