--- a/browser/base/content/test/sanitize/browser_sanitize-timespans.js
+++ b/browser/base/content/test/sanitize/browser_sanitize-timespans.js
@@ -448,17 +448,18 @@ async function setupHistory() {
   addPlace("http://2hour.com/", "Less than 2 hours ago", now_uSec - 90 * kUsecPerMin);
   addPlace("http://2hour10minutes.com/", "2 hours 10 minutes ago", now_uSec - 130 * kUsecPerMin);
   addPlace("http://4hour.com/", "Less than 4 hours ago", now_uSec - 180 * kUsecPerMin);
   addPlace("http://4hour10minutes.com/", "4 hours 10 minutesago", now_uSec - 250 * kUsecPerMin);
 
   let today = new Date();
   today.setHours(0);
   today.setMinutes(0);
-  today.setSeconds(1);
+  today.setSeconds(0);
+  today.setMilliseconds(1);
   addPlace("http://today.com/", "Today", today.getTime() * 1000);
 
   let lastYear = new Date();
   lastYear.setFullYear(lastYear.getFullYear() - 1);
   addPlace("http://before-today.com/", "Before Today", lastYear.getTime() * 1000);
   await PlacesTestUtils.addVisits(places);
 }
 
@@ -559,17 +560,18 @@ async function setupFormHistory() {
 
   timestamp = now_uSec - 250 * kUsecPerMin;
   results = await searchEntries(["guid"], { fieldname: "4hour10minutes" });
   await update({ op: "update", firstUsed: timestamp, guid: results[0].guid });
 
   let today = new Date();
   today.setHours(0);
   today.setMinutes(0);
-  today.setSeconds(1);
+  today.setSeconds(0);
+  today.setMilliseconds(1);
   timestamp = today.getTime() * 1000;
   results = await searchEntries(["guid"], { fieldname: "today" });
   await update({ op: "update", firstUsed: timestamp, guid: results[0].guid });
 
   let lastYear = new Date();
   lastYear.setFullYear(lastYear.getFullYear() - 1);
   timestamp = lastYear.getTime() * 1000;
   results = await searchEntries(["guid"], { fieldname: "b4today" });
@@ -650,17 +652,18 @@ async function setupDownloads() {
   download.startTime = new Date(now_mSec - 250 * kMsecPerMin), // 250 minutes ago
   download.canceled = true;
   await publicList.add(download);
 
   // Add "today" download
   let today = new Date();
   today.setHours(0);
   today.setMinutes(0);
-  today.setSeconds(1);
+  today.setSeconds(0);
+  today.setMilliseconds(1);
 
   download = await Downloads.createDownload({
     source: "https://bugzilla.mozilla.org/show_bug.cgi?id=453440",
     target: "fakefile-today"
   });
   download.startTime = today, // 12:00:01 AM this morning
   download.canceled = true;
   await publicList.add(download);