Add test_dynamic_callback

Author: T4rk1n

tests/integration/callbacks/test_dynamic_callback.py

@@ -0,0 +1,39 @@
+from dash import html, Dash, Input, Output
+
+
+def test_dync001_dynamic_callback(dash_duo):
+    app = Dash()
+
+    app.layout = html.Div(
+        [
+            html.Div(id="output"),
+            html.Button("create", id="create"),
+            html.Div("initial", id="output-2"),
+            html.Button("dynamic", id="dynamic"),
+        ]
+    )
+
+    @app.callback(
+        Output("output", "children"),
+        Input("create", "n_clicks"),
+        _allow_dynamic_callbacks=True,
+        prevent_initial_call=True,
+    )
+    def on_click(n_clicks):
+        @app.callback(
+            Output("output-2", "children"),
+            Input("dynamic", "n_clicks"),
+            prevent_initial_call=True,
+        )
+        def on_click2(n_clicks2):
+            return f"Dynamic clicks {n_clicks2}"
+
+        return f"creator {n_clicks}"
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_element("#create").click()
+    dash_duo.wait_for_text_to_equal("#output", "creator 1")
+
+    dash_duo.wait_for_element("#dynamic").click()
+    dash_duo.wait_for_text_to_equal("#output-2", "Dynamic clicks 1")