1 files changed, 124 insertions, 0 deletions
diff --git a/intl/locale/tests/LangPackMatcherTestUtils.sys.mjs b/intl/locale/tests/LangPackMatcherTestUtils.sys.mjs
new file mode 100644
index 0000000000..4b18f1be13
--- /dev/null
+++ b/intl/locale/tests/LangPackMatcherTestUtils.sys.mjs
@@ -0,0 +1,124 @@
+/* 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/. */
+
+import { LangPackMatcher } from "resource://gre/modules/LangPackMatcher.sys.mjs";
+
+/**
+ * LangPackMatcher.jsm calls out to to the addons store, which involves network requests.
+ * Other tests create a fake addons server, and install mock XPIs. At the time of this
+ * writing that infrastructure is not available for mochitests.
+ *
+ * Instead, this test mocks out APIs that have a side-effect, so the addons of the browser
+ * are never modified.
+ *
+ * The calls to get the app's locale and system's locale are also mocked so that the
+ * different language mismatch scenarios can be run through.
+ *
+ * The locales are BCP 47 identifiers:
+ *
+ * @param {{
+ *   sandbox: SinonSandbox,
+ *   systemLocale: string,
+ *   appLocale, string,
+ * }}
+ */
+export function getAddonAndLocalAPIsMocker(testScope, sandbox) {
+  const { info } = testScope;
+  return function mockAddonAndLocaleAPIs({ systemLocale, appLocale }) {
+    info("Mocking LangPackMatcher.jsm APIs");
+
+    let resolveLangPacks;
+    const langPackPromise = new Promise(resolve => {
+      resolveLangPacks = availableLangpacks => {
+        info(
+          `Resolving which langpacks are available for download: ${JSON.stringify(
+            availableLangpacks
+          )}`
+        );
+        resolve(
+          availableLangpacks.map(locale => ({
+            guid: `langpack-${locale}@firefox.mozilla.org`,
+            type: "language",
+            hash: locale,
+            target_locale: locale,
+            current_compatible_version: {
+              files: [
+                {
+                  platform: "all",
+                  url: `http://example.com/${locale}.langpack.xpi`,
+                },
+              ],
+            },
+          }))
+        );
+      };
+    });
+
+    let resolveInstaller;
+    const installerPromise = new Promise(resolve => {
+      resolveInstaller = () => {
+        info("LangPack install finished.");
+        resolve();
+      };
+    });
+
+    const { mockable } = LangPackMatcher;
+    if (appLocale) {
+      const availableLocales = [appLocale];
+      if (appLocale !== "en-US") {
+        // Ensure the fallback behavior is accurately simulated for Firefox.
+        availableLocales.push("en-US");
+      }
+      sandbox
+        .stub(mockable, "getAvailableLocalesIncludingFallback")
+        .returns(availableLocales);
+      sandbox.stub(mockable, "getDefaultLocale").returns(appLocale);
+      sandbox.stub(mockable, "getAppLocaleAsBCP47").returns(appLocale);
+      sandbox.stub(mockable, "getLastFallbackLocale").returns("en-US");
+    }
+    if (systemLocale) {
+      sandbox.stub(mockable, "getSystemLocale").returns(systemLocale);
+    }
+
+    sandbox.stub(mockable, "getAvailableLangpacks").callsFake(() => {
+      info("Requesting which langpacks are available for download");
+      return langPackPromise;
+    });
+
+    sandbox.stub(mockable, "installLangPack").callsFake(langPack => {
+      info(`LangPack install started, but pending: ${langPack.target_locale}`);
+      return installerPromise;
+    });
+
+    sandbox.stub(mockable, "setRequestedAppLocales").callsFake(locales => {
+      info(
+        `Changing the browser's requested locales to: ${JSON.stringify(
+          locales
+        )}`
+      );
+    });
+
+    return {
+      /**
+       * Resolves the addons API call with available langpacks. Call with a list
+       * of BCP 47 identifiers.
+       *
+       * @type {(availableLangpacks: string[]) => {}}
+       */
+      resolveLangPacks,
+
+      /**
+       * Resolves the pending call to install a langpack.
+       *
+       * @type {() => {}}
+       */
+      resolveInstaller,
+
+      /**
+       * The mocked APIs.
+       */
+      mockable,
+    };
+  };
+}