Bug 1860427 - Add a new environment to ESLint for testharness.js and automatically use it for html files including the harness. r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D191581

docs/code-quality/lint/linters/eslint-plugin-mozilla/environment.rst

@@ -70,6 +70,21 @@ special-powers-sandbox
 Defines the environment for scripts evaluated inside ``SpecialPowers`` sandbox
 with the default options.
 
+testharness
+-----------
+
+Defines the environment the globals that are injected from
+:searchfox:`dom/imptests/testharness.js <dom/imptests/testharness.js>`.
+
+It is injected automatically into (x)html files which include:
+
+.. code-block:: html
+
+    <script src="/resources/testharness.js"></script>
+
+It may need to be included manually in JavaScript files which are loaded into
+the same scope.
+
 xpcshell
 --------
 

tools/lint/eslint/eslint-plugin-mozilla/lib/environments/testharness.js

@@ -0,0 +1,61 @@
+/**
+ * @fileoverview Defines the environment for testharness.js files. This
+ * is automatically included in (x)html files including
+ * /resources/testharness.js.
+ *
+ * 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";
+
+// These globals are taken from dom/imptests/testharness.js, via the expose
+// function.
+
+module.exports = {
+  globals: {
+    EventWatcher: false,
+    test: false,
+    async_test: false,
+    promise_test: false,
+    promise_rejects: false,
+    generate_tests: false,
+    setup: false,
+    done: false,
+    on_event: false,
+    step_timeout: false,
+    format_value: false,
+    assert_true: false,
+    assert_false: false,
+    assert_equals: false,
+    assert_not_equals: false,
+    assert_in_array: false,
+    assert_object_equals: false,
+    assert_array_equals: false,
+    assert_approx_equals: false,
+    assert_less_than: false,
+    assert_greater_than: false,
+    assert_between_exclusive: false,
+    assert_less_than_equal: false,
+    assert_greater_than_equal: false,
+    assert_between_inclusive: false,
+    assert_regexp_match: false,
+    assert_class_string: false,
+    assert_exists: false,
+    assert_own_property: false,
+    assert_not_exists: false,
+    assert_inherits: false,
+    assert_idl_attribute: false,
+    assert_readonly: false,
+    assert_throws: false,
+    assert_unreaded: false,
+    assert_any: false,
+    fetch_tests_from_worker: false,
+    timeout: false,
+    add_start_callback: false,
+    add_test_state_callback: false,
+    add_result_callback: false,
+    add_completion_callback: false,
+  },
+};

tools/lint/eslint/eslint-plugin-mozilla/lib/globals.js

@@ -12,6 +12,7 @@ const path = require("path");
 const fs = require("fs");
 const helpers = require("./helpers");
 const htmlparser = require("htmlparser2");
+const testharnessEnvironment = require("./environments/testharness.js");
 
 const callExpressionDefinitions = [
   /^loader\.lazyGetter\((?:globalThis|this), "(\w+)"/,
@@ -323,6 +324,11 @@ function getGlobalsForScript(src, type, dir) {
     scriptName = path.join(helpers.rootDir, "testing", "mochitest", src);
   } else if (src.startsWith("/tests/")) {
     scriptName = path.join(helpers.rootDir, src.substring(7));
+  } else if (src.startsWith("/resources/testharness.js")) {
+    return Object.keys(testharnessEnvironment.globals).map(name => ({
+      name,
+      writable: true,
+    }));
   } else if (dir) {
     // Fallback to hoping this is a relative path.
     scriptName = path.join(dir, src);

tools/lint/eslint/eslint-plugin-mozilla/lib/index.js

@@ -27,13 +27,14 @@ module.exports = {
     "chrome-worker": require("../lib/environments/chrome-worker.js"),
     "frame-script": require("../lib/environments/frame-script.js"),
     jsm: require("../lib/environments/jsm.js"),
+    privileged: require("../lib/environments/privileged.js"),
     "process-script": require("../lib/environments/process-script.js"),
     "remote-page": require("../lib/environments/remote-page.js"),
     simpletest: require("../lib/environments/simpletest.js"),
     sjs: require("../lib/environments/sjs.js"),
     "special-powers-sandbox": require("../lib/environments/special-powers-sandbox.js"),
     specific: require("../lib/environments/specific"),
-    privileged: require("../lib/environments/privileged.js"),
+    testharness: require("../lib/environments/testharness.js"),
     xpcshell: require("../lib/environments/xpcshell.js"),
   },
   rules: {