diff --git a/toolkit/devtools/server/tests/unit/test_dbgglobal.js b/toolkit/devtools/server/tests/unit/test_dbgglobal.js
index 7efde3f03b4..6eb3fbb2676 100644
--- a/toolkit/devtools/server/tests/unit/test_dbgglobal.js
+++ b/toolkit/devtools/server/tests/unit/test_dbgglobal.js
@@ -9,7 +9,7 @@ function run_test()
   // Should get an exception if we try to interact with DebuggerServer
   // before we initialize it...
   check_except(function() {
-    DebuggerServer.openListener(2929);
+    DebuggerServer.openListener(-1);
   });
   check_except(DebuggerServer.closeListener);
   check_except(DebuggerServer.connectPipe);
@@ -20,7 +20,7 @@ function run_test()
   // These should still fail because we haven't added a createRootActor
   // implementation yet.
   check_except(function() {
-    DebuggerServer.openListener(2929);
+    DebuggerServer.openListener(-1);
   });
   check_except(DebuggerServer.closeListener);
   check_except(DebuggerServer.connectPipe);
@@ -28,7 +28,7 @@ function run_test()
   DebuggerServer.addActors("resource://test/testactors.js");
 
   // Now they should work.
-  DebuggerServer.openListener(2929);
+  DebuggerServer.openListener(-1);
   DebuggerServer.closeListener();
 
   // Make sure we got the test's root actor all set up.