Merge pull request #1249 from plotly/919-pytest-flake8

fix #919 - protect against pytest item with no funcargs

Author: alexcjohnson

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - [#1237](https://github.com/plotly/dash/pull/1237) Closes [#920](https://github.com/plotly/dash/issues/920): Converts hot reload fetch failures into a server status indicator showing whether the latest fetch succeeded or failed. Callback fetch failures still appear as errors but have a clearer message.
 
 ### Fixed
+- [#1249](https://github.com/plotly/dash/pull/1249) Fixes [#919](https://github.com/plotly/dash/issues/919) so `dash.testing` is compatible with more `pytest` plugins, particularly `pytest-flake8` and `pytest-black`.
 - [#1248](https://github.com/plotly/dash/pull/1248) Fixes [#1245](https://github.com/plotly/dash/issues/1245), so you can use prop persistence with components that have dict IDs, ie for pattern-matching callbacks.
 
 ## [1.12.0] - 2020-05-05

dash/testing/plugin.py

@@ -75,7 +75,7 @@ def pytest_runtest_makereport(item, call):  # pylint: disable=unused-argument
     rep = outcome.get_result()
 
     # we only look at actual failing test calls, not setup/teardown
-    if rep.when == "call" and rep.failed:
+    if rep.when == "call" and rep.failed and hasattr(item, "funcargs"):
         for name, fixture in item.funcargs.items():
             try:
                 if name in {"dash_duo", "dash_br", "dashr"}: