🚨 add test / fix rounding

Author: rpkyle

R/dash.R

@@ -1272,7 +1272,7 @@ Dash <- R6::R6Class(
         self$server$on('request', function(server, request, ...) {
           timing_information <- self$server$get_data('timing-information')
           dash_total <- timing_information[['__dash_server']]
-          timing_information[['__dash_server']][['dur']] <- round(as.numeric(Sys.time() - dash_total[['dur']]) * 1000)
+          timing_information[['__dash_server']][['dur']] <- round((as.numeric(Sys.time()) - dash_total[['dur']]) * 1000)
 
           header_as_string <- list()
 

tests/integration/test_callback_instrumentation.py

@@ -0,0 +1,59 @@
+from selenium.webdriver.support.select import Select
+from time import sleep
+import os, requests
+
+
+app = """
+ library(dash)
+ library(dashHtmlComponents)
+ library(dashCoreComponents)
+
+ app <- Dash$new()
+
+ app$layout(htmlDiv(
+   list(
+        htmlDiv(children = "Hello world!",
+           id = "messageDiv"
+        ),
+        htmlDiv(id = "emptyDiv")
+    )
+   )
+ )
+
+ app$callback(output = list(id="emptyDiv", property="children"),
+              params = list(input(id="messageDiv", property="children")),
+     function(y) {
+       app$callback_context.record_timing("pancakes", 1.23)
+       Sys.sleep(0.5)
+       return(y)
+     }
+ )
+
+ app$run_server(debug=TRUE)
+"""
+
+def test_rstm001_test_meta(dashr):
+    dashr.start_server(app)
+    dashr.wait_for_text_to_equal(
+        "#messageDiv",
+        "Hello world!"
+    )
+
+    response = requests.post(
+        "http://127.0.0.1:8050" + "/_dash-update-component",
+        json={
+            "output": "emptyDiv.children",
+            "outputs": {"id": "emptyDiv", "property": "children"},
+            "inputs": [{"id": "messageDiv", "property": "children", "value": 9}],
+            "changedPropIds": ["messageDiv.children"],
+        },
+    )
+    # eg 'Server-Timing': '__dash_server;dur=505, pancakes;dur=1230'
+    assert "Server-Timing" in response.headers
+    
+    st = response.headers["Server-Timing"]
+    times = {k: int(float(v)) for k, v in [p.split(";dur=") for p in st.split(", ")]}
+    assert "pancakes" in times
+    assert times["pancakes"] == 1230
+    assert "__dash_server" in times
+    assert times["__dash_server"] >= 500  # 0.5 sec wait