diff --git a/js/xpconnect/tests/unit/test_allowedDomains.js b/js/xpconnect/tests/unit/test_allowedDomains.js
index 163b2ca9a1e..a85d9d75a5d 100644
--- a/js/xpconnect/tests/unit/test_allowedDomains.js
+++ b/js/xpconnect/tests/unit/test_allowedDomains.js
@@ -41,6 +41,7 @@ function run_test() {
   evalAndCatch("objMaster.prop1", sbSubset);
   
   // Bug 777705:
+  sbMaster.Components = cu.getComponentsForScope(sbMaster);
   Components.utils.evalInSandbox("Components.interfaces", sbMaster);
   do_check_true(true);
 }
diff --git a/js/xpconnect/tests/unit/test_components.js b/js/xpconnect/tests/unit/test_components.js
index 72fdb13f4ab..5bd1b62bbb5 100644
--- a/js/xpconnect/tests/unit/test_components.js
+++ b/js/xpconnect/tests/unit/test_components.js
@@ -6,6 +6,11 @@ function run_test() {
   var sb4 = Cu.Sandbox("http://www.other.com");
   var rv;
 
+  // Components is normally hidden from content on the XBL scope chain, but we
+  // expose it to content here to make sure that the security wrappers work
+  // regardless.
+  [sb1, sb2, sb4].forEach(function(x) { x.Components = Cu.getComponentsForScope(x); });
+
   // non-chrome accessing chrome Components
   sb1.C = Components;
   rv = Cu.evalInSandbox("C.utils", sb1);
@@ -40,4 +45,4 @@ function run_test() {
   rv = Cu.evalInSandbox("C2.utils", sb1);
   do_check_eq(rv, undefined);
 
-}
\ No newline at end of file
+}