✨ add test for dashNoUpdate()

tests/integration/callbacks/test_no_update.py

@@ -0,0 +1,63 @@
+from selenium.webdriver.support.select import Select
+
+app = """
+library(dash)
+library(dashHtmlComponents)
+library(dashCoreComponents)
+
+app <- Dash$new()
+
+app$layout(
+  htmlDiv(list(
+    dccDropdown(options = list(
+      list(label = "Red", value = "#FF0000"),
+      list(label = "Green", value = "#00FF00"),      
+      list(label = "Blue", value = "#0000FF"),
+      list(label = "Do nothing", value = "nothing")
+    ),
+    id = "color-selector"),
+    htmlDiv(id='message-box',
+            children='Please select a colour choice from the dropdown menu.')
+  )
+  )
+)
+
+app$callback(output=list(id='message-box', property='children'),
+             params=list(
+               input(id='color-selector', property='value')),
+             function(color)
+             {
+               if (color %in% c("#FF0000", "#00FF00", "#0000FF")) {
+                 msg <- sprintf("The hexadecimal representation of your last chosen colour is %s",
+                                color)
+                 return(msg)
+               } else {
+                 return(dashNoUpdate())
+               }
+             }
+)
+
+app$run_server()
+"""
+
+
+def test_rsnu001_no_update(dashr):
+    dashr.start_server(app)
+    dashr.find_element("#color-selector").click()
+    dashr.find_elements("div.VirtualizedSelectOption")[0].click()
+    assert dashr.find_element("#message-box").text == "The hexadecimal representation of your last chosen colour is #FF0000"
+    dashr.find_element("#color-selector").click()
+    dashr.find_elements("div.VirtualizedSelectOption")[3].click()
+    assert dashr.find_element("#message-box").text == "The hexadecimal representation of your last chosen colour is #FF0000"
+    dashr.find_element("#color-selector").click()
+    dashr.find_elements("div.VirtualizedSelectOption")[1].click()
+    assert dashr.find_element("#message-box").text == "The hexadecimal representation of your last chosen colour is #00FF00"
+    dashr.find_element("#color-selector").click()
+    dashr.find_elements("div.VirtualizedSelectOption")[3].click()
+    assert dashr.find_element("#message-box").text == "The hexadecimal representation of your last chosen colour is #00FF00"
+    dashr.find_element("#color-selector").click()
+    dashr.find_elements("div.VirtualizedSelectOption")[2].click()
+    assert dashr.find_element("#message-box").text == "The hexadecimal representation of your last chosen colour is #0000FF"
+    dashr.find_element("#color-selector").click()
+    dashr.find_elements("div.VirtualizedSelectOption")[3].click()
+    assert dashr.find_element("#message-box").text == "The hexadecimal representation of your last chosen colour is #0000FF"