Bug 561876: Some tests aren't clearing active installs leading to later tests failing. r=robstrong

toolkit/mozapps/extensions/test/browser/browser_installssl.js

@@ -45,6 +45,7 @@ function run_install_tests(callback) {
           is(SUCCESS, expectedStatus, message);
           run_next_install_test();
           // Don't proceed with the install
+          install.cancel();
           return false;
         },
 

toolkit/mozapps/extensions/test/xpinstall/head.js

@@ -81,7 +81,11 @@ var Harness = {
       win.close();
 
     AddonManager.removeInstallListener(this);
-    finish();
+
+    AddonManager.getAllInstalls(function(installs) {
+      is(installs.length, 0, "Should be no active installs at the end of the test");
+      finish();
+    });
   },
 
   endTest: function() {
@@ -169,6 +173,9 @@ var Harness = {
       installInfo.install();
     }
     else {
+      installInfo.installs.forEach(function(install) {
+        install.cancel();
+      });
       this.endTest();
     }
   },