--- a/tools/lint/eslint/eslint-plugin-mozilla/lib/helpers.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/helpers.js
@@ -434,18 +434,26 @@ module.exports = {
    *         An array of objects with file and manifest properties
    */
   getManifestsForDirectory(dir) {
     if (directoryManifests.has(dir)) {
       return directoryManifests.get(dir);
     }
 
     let manifests = [];
+    let names = [];
+    try {
+      names = fs.readdirSync(dir);
+    } catch (err) {
+      // Ignore directory not found, it might be faked by a test
+      if (err.code !== "ENOENT") {
+        throw err;
+      }
+    }
 
-    let names = fs.readdirSync(dir);
     for (let name of names) {
       if (!name.endsWith(".ini")) {
         continue;
       }
 
       try {
         let manifest = ini.parse(fs.readFileSync(path.join(dir, name), "utf8"));
 

--- a/tools/lint/eslint/eslint-plugin-mozilla/lib/index.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/index.js
@@ -38,16 +38,17 @@ module.exports = {
     "import-browser-window-globals":
       require("../lib/rules/import-browser-window-globals"),
     "import-content-task-globals":
       require("../lib/rules/import-content-task-globals"),
     "import-globals": require("../lib/rules/import-globals"),
     "import-headjs-globals": require("../lib/rules/import-headjs-globals"),
     "mark-test-function-used": require("../lib/rules/mark-test-function-used"),
     "no-aArgs": require("../lib/rules/no-aArgs"),
+    "no-arbitrary-setTimeout": require("../lib/rules/no-arbitrary-setTimeout"),
     "no-cpows-in-tests": require("../lib/rules/no-cpows-in-tests"),
     "no-single-arg-cu-import": require("../lib/rules/no-single-arg-cu-import"),
     "no-import-into-var-and-global":
       require("../lib/rules/no-import-into-var-and-global.js"),
     "no-task": require("../lib/rules/no-task"),
     "no-useless-parameters": require("../lib/rules/no-useless-parameters"),
     "no-useless-removeEventListener":
       require("../lib/rules/no-useless-removeEventListener"),
@@ -65,16 +66,17 @@ module.exports = {
     "avoid-nsISupportsString-preferences": "off",
     "balanced-listeners": "off",
     "import-browser-window-globals": "off",
     "import-content-task-globals": "off",
     "import-globals": "off",
     "import-headjs-globals": "off",
     "mark-test-function-used": "off",
     "no-aArgs": "off",
+    "no-arbitrary-setTimeout": "off",
     "no-cpows-in-tests": "off",
     "no-single-arg-cu-import": "off",
     "no-import-into-var-and-global": "off",
     "no-task": "off",
     "no-useless-parameters": "off",
     "no-useless-removeEventListener": "off",
     "reject-importGlobalProperties": "off",
     "reject-some-requires": "off",

new file mode 100644
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/rules/no-arbitrary-setTimeout.js
@@ -0,0 +1,65 @@
+/**
+ * @fileoverview Reject use of non-zero values in setTimeout
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var helpers = require("../helpers");
+
+module.exports = {
+  meta: {
+    docs: {
+      description: "disallow setTimeout with non-zero values in tests",
+      category: "Best Practices"
+    },
+    schema: []
+  },
+
+  // ---------------------------------------------------------------------------
+  // Public
+  //  --------------------------------------------------------------------------
+
+  create(context) {
+    return {
+      "CallExpression": function(node) {
+        // We don't want to run this on mochitests as mochitest already
+        // prevents flaky setTimeout at runtime. This check is built-in
+        // to the rule itself as sometimes xpcshell tests can live
+        // alongside mochitests and so can't be configured via config.
+        if (helpers.getTestType(context) !== "xpcshell") {
+          return;
+        }
+
+        let callee = node.callee;
+        if (callee.type === "MemberExpression") {
+          if (callee.property.name !== "setTimeout" ||
+              callee.object.name !== "window" ||
+              node.arguments.length < 2) {
+            return;
+          }
+        } else if (callee.type === "Identifier") {
+          if (callee.name !== "setTimeout" ||
+              node.arguments.length < 2) {
+            return;
+          }
+        } else {
+          return;
+        }
+
+        let timeout = node.arguments[1];
+        if (timeout.type !== "Literal" || timeout.value > 0) {
+          context.report(node, "listen for events instead of setTimeout() " +
+                               "with arbitrary delay");
+        }
+      }
+    };
+  }
+};

new file mode 100644
--- /dev/null
+++ b/tools/lint/eslint/eslint-plugin-mozilla/tests/no-arbitrary-setTimeout.js
@@ -0,0 +1,41 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var rule = require("../lib/rules/no-arbitrary-setTimeout");
+var RuleTester = require("eslint/lib/testers/rule-tester");
+
+const ruleTester = new RuleTester({ parserOptions: { ecmaVersion: 6 } });
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+function wrapCode(code, filename = "xpcshell/test_foo.js") {
+  return {code, filename};
+}
+
+function invalidCode(code) {
+  let message = "listen for events instead of setTimeout() with arbitrary delay";
+  let obj = wrapCode(code);
+  obj.errors = [{message, type: "CallExpression"}];
+  return obj;
+}
+
+ruleTester.run("no-arbitrary-setTimeout", rule, {
+  valid: [
+    wrapCode("setTimeout(function() {}, 0);"),
+    wrapCode("setTimeout(function() {});"),
+    wrapCode("setTimeout(function() {}, 10);", "browser_test.js")
+  ],
+  invalid: [
+    invalidCode("setTimeout(function() {}, 10);"),
+    invalidCode("setTimeout(function() {}, timeout);")
+  ]
+});
+