Add test dropdown remove options.

Author: T4rk1n

Diff for: components/dash-core-components/tests/integration/dropdown/test_remove_option.py

@@ -0,0 +1,92 @@
+import json
+
+from dash import Dash, html, dcc, Output, Input
+from dash.exceptions import PreventUpdate
+
+
+sample_dropdown_options = [
+    {"label": "New York City", "value": "NYC"},
+    {"label": "Montreal", "value": "MTL"},
+    {"label": "San Francisco", "value": "SF"},
+]
+
+
+def test_ddro001_remove_option_single(dash_dcc):
+    dropdown_options = sample_dropdown_options
+
+    app = Dash(__name__)
+    value = 'SF'
+
+    app.layout = html.Div([
+        dcc.Dropdown(
+            options=dropdown_options,
+            value=value,
+            id='dropdown',
+        ),
+        html.Button('Remove option', id='remove'),
+        html.Div(id='value-output')
+    ])
+
+    @app.callback(
+        Output('dropdown', 'options'),
+        [Input('remove', 'n_clicks')]
+    )
+    def on_click(n_clicks):
+        if not n_clicks:
+            raise PreventUpdate
+        return sample_dropdown_options[:-1]
+
+    @app.callback(
+        Output('value-output', 'children'),
+        [Input('dropdown', 'value')]
+    )
+    def on_change(val):
+        if not val:
+            raise PreventUpdate
+        return val or 'None'
+
+    dash_dcc.start_server(app)
+    btn = dash_dcc.wait_for_element('#remove')
+    btn.click()
+
+    dash_dcc.wait_for_text_to_equal('#value-output', 'None')
+
+
+def test_ddro002_remove_option_multi(dash_dcc):
+    dropdown_options = sample_dropdown_options
+
+    app = Dash(__name__)
+    value = ['MTL', 'SF']
+
+    app.layout = html.Div([
+        dcc.Dropdown(
+            options=dropdown_options,
+            value=value,
+            multi=True,
+            id='dropdown',
+        ),
+        html.Button('Remove option', id='remove'),
+        html.Div(id='value-output')
+    ])
+
+    @app.callback(
+        Output('dropdown', 'options'),
+        [Input('remove', 'n_clicks')]
+    )
+    def on_click(n_clicks):
+        if not n_clicks:
+            raise PreventUpdate
+        return sample_dropdown_options[:-1]
+
+    @app.callback(
+        Output('value-output', 'children'),
+        [Input('dropdown', 'value')]
+    )
+    def on_change(val):
+        return json.dumps(val)
+
+    dash_dcc.start_server(app)
+    btn = dash_dcc.wait_for_element('#remove')
+    btn.click()
+
+    dash_dcc.wait_for_text_to_equal('#value-output', '["MTL"]')