`msg:` in failure mock causes TypeError: got multiple values for keyword argument `msg`

[jorge-romero]

Summary

When a scenario mock includes msg: in a success: false response, the framework crashes with TypeError: fail_json() got multiple values for keyword argument 'msg'. This is caused by fail_json receiving msg both as an explicit keyword argument and again via **response_data.

Affected file

ansible_playtest/ansible_mocker/mock_ansible_adapter.py

error_msg = response_data.get("error_message", "Mock service failure")
module.fail_json(msg=error_msg, **response_data)
# ↑ if response_data still contains 'msg:', Python raises TypeError

Reproducer

Scenario YAML:

service_mocks:
  my_module:
    success: false
    msg: "Connection refused"   # ← triggers the crash

Running any test with this scenario raises:

TypeError: fail_json() got multiple values for keyword argument 'msg'

Expected behaviour

The framework should either:

• Document that msg: is a reserved key and raise a clear validation error at scenario-load time, or
• Consume msg from response_data before calling fail_json (e.g. prefer it as error_msg if present).

Suggested fix

# Pop 'msg' from response_data to avoid the collision
error_msg = response_data.pop("msg", None) or response_data.pop("error_message", "Mock service failure")
module.fail_json(msg=error_msg, **response_data)

Workaround

Use error_message: instead of msg: in all success: false mock responses.