diff -r 000000000000 -r 6474c204b198 toolkit/devtools/server/tests/unit/test_trace_actor-03.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/devtools/server/tests/unit/test_trace_actor-03.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,67 @@
+/* Any copyright is dedicated to the Public Domain.
+ http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests that automatically generated names for traces are unique.
+ */
+
+var gDebuggee;
+var gClient;
+var gTraceClient;
+
+function run_test()
+{
+  initTestTracerServer();
+  gDebuggee = addTestGlobal("test-tracer-actor");
+  gClient = new DebuggerClient(DebuggerServer.connectPipe());
+  gClient.connect(function() {
+    attachTestTab(gClient, "test-tracer-actor", function(aResponse, aTabClient) {
+      gClient.attachTracer(aResponse.traceActor, function(aResponse, aTraceClient) {
+        gTraceClient = aTraceClient;
+        test_unique_generated_trace_names();
+      });
+    });
+  });
+  do_test_pending();
+}
+
+function test_unique_generated_trace_names()
+{
+  let deferred = promise.defer();
+  deferred.resolve([]);
+
+  let p = deferred.promise, traces = 50;
+  for (let i = 0; i < traces; i++)
+    p = p.then(start_trace);
+  for (let i = 0; i < traces; i++)
+    p = p.then(stop_trace);
+
+  p = p.then(function() {
+    finishClient(gClient);
+  });
+}
+
+function start_trace(aTraceNames)
+{
+  let deferred = promise.defer();
+  gTraceClient.startTrace([], null, function(aResponse) {
+    let hasDuplicates = aTraceNames.some(name => name === aResponse.name);
+    do_check_true(!hasDuplicates, "Generated trace names should be unique");
+    aTraceNames.push(aResponse.name);
+    deferred.resolve(aTraceNames);
+  });
+  return deferred.promise;
+}
+
+function stop_trace(aTraceNames)
+{
+  let deferred = promise.defer();
+  gTraceClient.stopTrace(null, function(aResponse) {
+    do_check_eq(aTraceNames.pop(), aResponse.name,
+                "Stopped trace should be most recently started trace");
+    let hasDuplicates = aTraceNames.some(name => name === aResponse.name);
+    do_check_true(!hasDuplicates, "Generated trace names should be unique");
+    deferred.resolve(aTraceNames);
+  });
+  return deferred.promise;
+}