Use xfail for flaky tests.

Author: T4rk1n

components/dash-core-components/tests/integration/calendar/test_date_picker_single.py

@@ -1,6 +1,8 @@
 from datetime import datetime, timedelta
 
 import pytest
+import werkzeug
+
 from dash import Dash, Input, Output, html, dcc, no_update
 
 
@@ -71,6 +73,11 @@ def test_dtps010_local_and_session_persistence(dash_dcc):
     assert dash_dcc.get_logs() == []
 
 
+@pytest.mark.xfail(
+    condition=werkzeug.__version__ in ("2.1.0", "2.1.1"),
+    reason="Bug with 204 and Transfer-Encoding",
+    strict=False,
+)
 def test_dtps011_memory_persistence(dash_dcc):
     app = Dash(__name__)
     app.layout = html.Div(

components/dash-core-components/tests/integration/store/test_data_lifecycle.py

@@ -1,6 +1,14 @@
+import pytest
+import werkzeug
+
 import dash.testing.wait as wait
 
 
+@pytest.mark.xfail(
+    condition=werkzeug.__version__ in ("2.1.0", "2.1.1"),
+    reason="Bug with 204 and Transfer-Encoding",
+    strict=False,
+)
 def test_stdl001_data_lifecycle_with_different_condition(store_app, dash_dcc):
     dash_dcc.start_server(store_app)
 

components/dash-core-components/tests/integration/tab/test_tabs_with_graphs.py

@@ -1,3 +1,5 @@
+import werkzeug
+
 from dash import Dash, Input, Output, dcc, html
 from dash.exceptions import PreventUpdate
 import json
@@ -119,6 +121,11 @@ def render_content(tab):
     assert dash_dcc.get_logs() == []
 
 
+@pytest.mark.xfail(
+    condition=werkzeug.__version__ in ("2.1.0", "2.1.1"),
+    reason="Bug with 204 and Transfer-Encoding",
+    strict=False,
+)
 @pytest.mark.parametrize("is_eager", [True, False])
 def test_tabs_render_without_selected(dash_dcc, is_eager):
     app = Dash(__name__, eager_loading=is_eager)

tests/integration/callbacks/test_basic_callback.py

@@ -3,6 +3,8 @@
 import pytest
 import time
 
+import werkzeug
+
 from dash_test_components import (
     AsyncComponent,
     CollapseComponent,
@@ -312,6 +314,11 @@ def set_out(opts):
             dash_duo.select_dcc_dropdown("#dd", "opt{}".format(i))
 
 
+@pytest.mark.xfail(
+    condition=werkzeug.__version__ in ("2.1.0", "2.1.1"),
+    reason="Bug with 204 and Transfer-Encoding",
+    strict=False,
+)
 @pytest.mark.parametrize("refresh", [False, True])
 def test_cbsc007_parallel_updates(refresh, dash_duo):
     # This is a funny case, that seems to mostly happen with dcc.Location