diff -r 000000000000 -r 6474c204b198 dom/telephony/test/marionette/test_dsds_connection_conflict.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/telephony/test/marionette/test_dsds_connection_conflict.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,53 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+MARIONETTE_TIMEOUT = 60000;
+MARIONETTE_HEAD_JS = 'head.js';
+
+function muxModem(id) {
+  let deferred = Promise.defer();
+
+  emulator.run("mux modem " + id, function() {
+    deferred.resolve();
+  });
+
+  return deferred.promise;
+}
+
+function testNewCallWhenOtherConnectionInUse(firstServiceId, secondServiceId) {
+  log("= testNewCallWhenOtherConnectionInUse =");
+  log("1st call on " + firstServiceId + ", 2nd call on " + secondServiceId);
+
+  let outCall;
+
+  return Promise.resolve()
+    .then(() => muxModem(firstServiceId))
+    .then(() => {
+      return telephony.dial("0912345000", firstServiceId);
+    })
+    .then(call => {
+      outCall = call;
+      is(outCall.serviceId, firstServiceId);
+    })
+    .then(() => gRemoteAnswer(outCall))
+    .then(() => {
+      return telephony.dial("0912345001", secondServiceId);
+    })
+    .then(() => {
+      log("The promise should not be resolved");
+      ok(false);
+    }, cause => {
+      is(cause, "OtherConnectionInUse");
+    })
+    .then(() => gRemoteHangUp(outCall));
+}
+
+startDSDSTest(function() {
+  testNewCallWhenOtherConnectionInUse(0, 1)
+    .then(() => testNewCallWhenOtherConnectionInUse(1, 0))
+    .then(() => muxModem(0))
+    .then(null, () => {
+      ok(false, "promise rejects during test.");
+    })
+    .then(finish);
+});