diff -r 000000000000 -r 6474c204b198 browser/devtools/netmonitor/test/browser_net_timing-division.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/netmonitor/test/browser_net_timing-division.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,64 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests if timing intervals are divided againts seconds when appropriate.
+ */
+
+function test() {
+  initNetMonitor(CUSTOM_GET_URL).then(([aTab, aDebuggee, aMonitor]) => {
+    info("Starting test... ");
+
+    let { $all, NetMonitorView } = aMonitor.panelWin;
+    let { RequestsMenu } = NetMonitorView;
+
+    RequestsMenu.lazyUpdate = false;
+
+    waitForNetworkEvents(aMonitor, 2).then(() => {
+      let millisecondDivs = $all(".requests-menu-timings-division[division-scale=millisecond]");
+      let secondDivs = $all(".requests-menu-timings-division[division-scale=second]");
+      let minuteDivs = $all(".requests-menu-timings-division[division-scale=minute]");
+
+      info("Number of millisecond divisions: " + millisecondDivs.length);
+      info("Number of second divisions: " + secondDivs.length);
+      info("Number of minute divisions: " + minuteDivs.length);
+
+      for (let div of millisecondDivs) {
+        info("Millisecond division: " + div.getAttribute("value"));
+      }
+      for (let div of secondDivs) {
+        info("Second division: " + div.getAttribute("value"));
+      }
+      for (let div of minuteDivs) {
+        info("Minute division: " + div.getAttribute("value"));
+      }
+
+      is(RequestsMenu.itemCount, 2,
+        "There should be only two requests made.");
+
+      let firstRequest = RequestsMenu.getItemAtIndex(0);
+      let lastRequest = RequestsMenu.getItemAtIndex(1);
+
+      info("First request happened at: " +
+        firstRequest.attachment.responseHeaders.headers.find(e => e.name == "Date").value);
+      info("Last request happened at: " +
+        lastRequest.attachment.responseHeaders.headers.find(e => e.name == "Date").value);
+
+      ok(secondDivs.length,
+        "There should be at least one division on the seconds time scale.");
+      ok(secondDivs[0].getAttribute("value").match(/\d+\.\d{2}\s\w+/),
+        "The division on the seconds time scale looks legit.");
+
+      teardown(aMonitor).then(finish);
+    });
+
+    aDebuggee.get(Math.random(), () => {
+      // Timeout needed for having enough divisions on the time scale.
+      setTimeout(() => {
+        aDebuggee.get(Math.random(), () => {
+          // Done.
+        });
+      }, 3000);
+    });
+  });
+}