Change CHANGELOG, add empty graph test.

Author: rmarren1

CHANGELOG.md

@@ -2,7 +2,9 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [0.28.1]
+## [0.28.1] - 2018-08-29
+### Changed
+- `candlestick` and `OHLC` charts are now plotted using the `Plotly.react` method instead of the `Plotly.newPlot` method.
 ### Fixed
 - Fix bug where front-end error was thrown when setting `Graph.figure = {}` (fixes [#260]).
 

test/IntegrationTests.py

@@ -11,6 +11,7 @@
 
 from selenium import webdriver
 from selenium.webdriver.chrome.options import Options
+from selenium.webdriver.support.ui import WebDriverWait
 
 
 class IntegrationTests(unittest.TestCase):
@@ -25,6 +26,7 @@ def setUpClass(cls):
             options.binary_location = os.environ['DASH_TEST_CHROMEPATH']
 
         cls.driver = webdriver.Chrome(chrome_options=options)
+        cls.wait = WebDriverWait(cls.driver, 20)
         loader = percy.ResourceLoader(webdriver=cls.driver)
         cls.percy_runner = percy.Runner(loader=loader)
         cls.percy_runner.initialize_build()

test/test_integration.py

@@ -12,8 +12,9 @@
 import dash_html_components as html
 import dash_core_components as dcc
 import dash_table_experiments as dt
-from selenium import webdriver
+from selenium.webdriver.common.by import By
 from selenium.webdriver.common.keys import Keys
+from selenium.webdriver.support import expected_conditions as EC
 from selenium.common.exceptions import InvalidElementStateException
 
 from textwrap import dedent
@@ -851,3 +852,30 @@ def on_click(n_clicks):
         time.sleep(2)
 
         self.driver.switch_to.alert.accept()
+
+    def test_empty_graph(self):
+        app = dash.Dash(__name__)
+
+        app.layout = html.Div([
+            html.Button(id='click', children='Click me'),
+            dcc.Graph(
+                id='graph',
+                figure={
+                    'data': dict(x=[1, 2, 3], y=[1, 2, 3])
+                }
+            )
+        ])
+
+        @app.callback(dash.dependencies.Output('graph', 'figure'),
+                      [dash.dependencies.Input('click', 'n_clicks')],
+                      [dash.dependencies.State('graph', 'figure')])
+        def render_content(click, prev_graph):
+            if click:
+                return {}
+            return prev_graph
+
+        self.startServer(app=app)
+        self.wait.until(EC.element_to_be_clickable((By.ID, 'click')))
+        self.driver.find_element_by_css_selector('#click').click()
+        time.sleep(2)  # Wait for graph to re-render
+        self.snapshot('render-empty-graph')