Bug 1389488 - Check that add-on file exists before forwarding request to AddonManager r=whimboo

MozReview-Commit-ID: 6b6QS9y6vPj

--HG--
extra : rebase_source : c4d2174ba11ddcc5076152982b761bb02ee94d65

testing/marionette/addon.js

@@ -91,6 +91,10 @@ addon.install = async function(path, temporary = false) {
   let file = new FileUtils.File(path);
   let addon;
 
+  if (!file.exists()) {
+    throw new UnknownError(`Could not find add-on at '${path}'`);
+  }
+
   try {
     if (temporary) {
       addon = await AddonManager.installTemporaryAddon(file);

testing/marionette/harness/marionette_harness/tests/unit/test_addons.py

@@ -91,3 +91,9 @@ class TestAddons(MarionetteTestCase):
 
         with self.assertRaises(AddonInstallException):
             self.addons.install(addon_path)
+
+    def test_install_nonexistent_addon(self):
+        addon_path = os.path.join(here, "does-not-exist.xpi")
+
+        with self.assertRaisesRegexp(AddonInstallException, "Could not find add-on at"):
+            self.addons.install(addon_path)