diff --git a/dom/security/test/csp/file_report_chromescript.js b/dom/security/test/csp/file_report_chromescript.js
index b9375a4dead5..a87ed258940c 100644
--- a/dom/security/test/csp/file_report_chromescript.js
+++ b/dom/security/test/csp/file_report_chromescript.js
@@ -46,9 +46,11 @@ var openingObserver = {
       }
 
       sendAsyncMessage('opening-request-completed', message);
-      Services.obs.removeObserver(openingObserver, 'http-on-opening-request');
     }
   }
 };
 
 Services.obs.addObserver(openingObserver, 'http-on-opening-request');
+addMessageListener("finish", function() {
+  Services.obs.removeObserver(openingObserver, 'http-on-opening-request');
+});
diff --git a/dom/security/test/csp/test_blocked_uri_in_reports.html b/dom/security/test/csp/test_blocked_uri_in_reports.html
index f68d8c03f23b..7e656509e244 100644
--- a/dom/security/test/csp/test_blocked_uri_in_reports.html
+++ b/dom/security/test/csp/test_blocked_uri_in_reports.html
@@ -57,6 +57,7 @@ script.addMessageListener('opening-request-completed', function ml(msg) {
   }
 
   script.removeMessageListener('opening-request-completed', ml);
+  script.sendAsyncMessage("finish");
   SimpleTest.finish();
 });
 
diff --git a/dom/security/test/csp/test_report.html b/dom/security/test/csp/test_report.html
index e8cfb8778061..7d3bd7dcc085 100644
--- a/dom/security/test/csp/test_report.html
+++ b/dom/security/test/csp/test_report.html
@@ -84,6 +84,7 @@ script.addMessageListener('opening-request-completed', function ml(msg) {
   }
 
   script.removeMessageListener('opening-request-completed', ml);
+  script.sendAsyncMessage("finish");
   SimpleTest.finish();
 });