1 files changed, 51 insertions, 0 deletions
diff --git a/dom/ipc/tests/test_Preallocated.html b/dom/ipc/tests/test_Preallocated.html
new file mode 100644
index 0000000000..fb719995f5
--- /dev/null
+++ b/dom/ipc/tests/test_Preallocated.html
@@ -0,0 +1,51 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+Test that the preallocated process starts up.
+-->
+<head>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="application/javascript" src="../browserElementTestHelpers.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+
+<script type="application/javascript">
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+
+function expectProcessCreated() {
+  /* eslint-env mozilla/chrome-script */
+  return new Promise(resolve => {
+    function parentExpectProcessCreated() {
+      let topic = "ipc:content-initializing";
+      let obs = { observe() {
+        Services.obs.removeObserver(obs, topic);
+        sendAsyncMessage("process-created");
+      }};
+      Services.obs.addObserver(obs, topic);
+    }
+
+    let helper = SpecialPowers.loadChromeScript(parentExpectProcessCreated);
+    SimpleTest.registerCleanupFunction(function() { helper.destroy(); });
+    helper.addMessageListener("process-created", resolve);
+  });
+}
+
+expectProcessCreated().then(() => {
+  ok(true, "Process creation detected.");
+  SimpleTest.finish();
+});
+
+// Kill existing preallocated process.
+SpecialPowers.pushPrefEnv({"set": [["dom.ipc.processPrelaunch.enabled", false]]}).then(() => {
+  // Make sure we have the capacity to launch preallocated process.
+  SpecialPowers.pushPrefEnv({"set": [["dom.ipc.processCount", 100]]}).then(() => {
+    // Enable preallocated process and run the test.
+    SpecialPowers.pushPrefEnv({"set": [["dom.ipc.processPrelaunch.enabled", true]]});
+  });
+});
+</script>
+</body>
+</html>