modernize race conditions test

Author: alexcjohnson

tests/integration/renderer/test_race_conditions.py

@@ -0,0 +1,57 @@
+import itertools
+import time
+import flask
+import pytest
+
+import dash_html_components as html
+import dash_core_components as dcc
+from dash import Dash
+from dash.dependencies import Input, Output
+
+
+DELAY_TIME = 0.2
+
+routes = [
+    "layout",
+    "dependencies",
+    "update-component",
+    "_config"
+    # routes and component-suites
+    # are other endpoints but are excluded to speed up tests
+]
+
+permuted_strs = [
+    ','.join(endpoints) for endpoints in itertools.permutations(routes, len(routes))
+]
+
+
+@pytest.mark.parametrize("permuted_str", permuted_strs)
+def test_rdrc001_race_conditions(dash_duo, permuted_str):
+    endpoints = permuted_str.split(',')
+    app = Dash(__name__)
+    app.layout = html.Div(
+        [
+            html.Div("Hello world", id="output"),
+            dcc.Input(id="input", value="initial value"),
+        ]
+    )
+
+    @app.callback(Output("output", "children"), Input("input", "value"))
+    def update(value):
+        return value
+
+    def delay():
+        for i, route in enumerate(endpoints):
+            if route in flask.request.path:
+                time.sleep((DELAY_TIME * i) + DELAY_TIME)
+
+    app.server.before_request(delay)
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_text_to_equal(
+        '#output',
+        "initial value",
+        timeout=DELAY_TIME * (len(endpoints) + 3) + 3
+    )
+
+    assert not dash_duo.get_logs()