adding test for allow_optional

Author: BSd3v

tests/integration/callbacks/test_callback_optional.py

@@ -0,0 +1,101 @@
+from dash import *
+
+def test_cbop001_optional_input(dash_duo):
+    app = Dash(suppress_callback_exceptions=True)
+
+    app.layout = html.Div(
+        [
+            html.Button(id='button1', children='Button 1'),
+            html.Div(id='button-container'),
+            html.Div(id='test-out'),
+            html.Div(id='test-out2')
+        ]
+    )
+
+    @app.callback(
+        Output('button-container', 'children'),
+        Input('button1', 'n_clicks'),
+        State('button-container', 'children'),
+        prevent_initial_call=True
+    )
+    def _(_, c):
+        if not c:
+            return html.Button(id='button2', children='Button 2')
+        return no_update
+
+    @app.callback(
+        Output('test-out', 'children'),
+        Input('button1', 'n_clicks'),
+        Input('button2', 'n_clicks', allow_optional=True),
+        prevent_inital_call=True
+    )
+    def display(n, n2):
+        return f"{n} - {n2}"
+
+    dash_duo.start_server(app)
+    dash_duo.wait_for_text_to_equal('#button1', 'Button 1')
+    assert dash_duo.get_logs() == []
+    dash_duo.wait_for_text_to_equal('#test-out', 'None - None')
+    dash_duo.find_element("#button1").click()
+    dash_duo.wait_for_text_to_equal('#test-out', '1 - None')
+
+    dash_duo.find_element("#button2").click()
+    dash_duo.wait_for_text_to_equal('#test-out', '1 - 1')
+    assert dash_duo.get_logs() == []
+
+
+
+def test_cbop002_optional_state(dash_duo):
+    app = Dash(suppress_callback_exceptions=True)
+
+    app.layout = html.Div(
+        [
+            html.Button(id='button1', children='Button 1'),
+            html.Div(id='button-container'),
+            html.Div(id='test-out'),
+            html.Div(id='test-out2')
+        ]
+    )
+
+    @app.callback(
+        Output('button-container', 'children'),
+        Input('button1', 'n_clicks'),
+        State('button-container', 'children'),
+        prevent_initial_call=True
+    )
+    def _(_, c):
+        if not c:
+            return html.Button(id='button2', children='Button 2')
+        return no_update
+
+    @app.callback(
+        Output('test-out', 'children'),
+        Input('button1', 'n_clicks'),
+        State('button2', 'n_clicks', allow_optional=True),
+        prevent_inital_call=True
+    )
+    def display(n, n2):
+        return f"{n} - {n2}"
+
+    @app.callback(
+        Output('test-out2', 'children'),
+        Input('button2', 'n_clicks', allow_optional=True)
+    )
+    def test(n):
+        if n:
+            return n
+        return no_update
+
+    dash_duo.start_server(app)
+    dash_duo.wait_for_text_to_equal('#button1', 'Button 1')
+    assert dash_duo.get_logs() == []
+    dash_duo.wait_for_text_to_equal('#test-out', 'None - None')
+    dash_duo.find_element("#button1").click()
+    dash_duo.wait_for_text_to_equal('#test-out', '1 - None')
+
+    dash_duo.find_element("#button2").click()
+    dash_duo.wait_for_text_to_equal('#test-out2', '1')
+    dash_duo.wait_for_text_to_equal('#test-out', '1 - None')
+    dash_duo.find_element("#button1").click()
+    dash_duo.wait_for_text_to_equal('#test-out', '2 - 1')
+    assert dash_duo.get_logs() == []