Issue 7236 - Handle sub properties in abort-on-property snippets

test/browser/snippets.js

Index: test/browser/snippets.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/test/browser/snippets.js
@@ -0,0 +1,99 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-present eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+"use strict";
+
+const library = require("../../lib/content/snippets.js");
+const {timeout} = require("./_utils");
+
+// We need this stub for the injector.
+window.browser = {
+  runtime: {
+    getURL: () => ""
+  }
+};
+
+async function runSnippet(test, snippetName, ...args)
+{
+  let snippet = library[snippetName];
+
+  test.ok(snippet);
+
+  snippet(...args);
+  await timeout(100);

[Manish Jethani, 2019/03/13 16:36:14]

Do we really need this timeout here?

[hub, 2019/03/14 10:28:05]

Without it, the test fail. With a 0 timeout, it fails just on Chrome.

[Manish Jethani, 2019/03/14 11:32:08]

Why is this though? Is it because the `<script>` element needs to be injected?

[hub, 2019/03/14 12:32:54]

that's what I think.

[Manish Jethani, 2019/03/16 10:50:24]

OK, I checked. It is indeed because the snippet returns before the code has
executed. Let's add a comment here then. Something like:

  // For snippets that run in the context of the document via a <script>
  // element (i.e. snippets that use makeInjector()), we need to wait for
  // execution to be complete.

[hub, 2019/03/18 18:27:26]

Done.

+}
+
+exports.testAbortPropertyReadSnippet = async function(test)

[Manish Jethani, 2019/03/13 16:36:14]

Nit: We should maybe name this `testAbortOnPropertyReadSnippet`.

[hub, 2019/03/14 10:28:05]

Done.

+{
+  window.abpTest = "foo";
+
+  async function testProperty(property, result = true)

[Manish Jethani, 2019/03/13 16:36:14]

This function doesn't have to be async from what I can tell.

[hub, 2019/03/14 10:28:05]

Done.

+  {
+    let properties = property.split(".");

[Manish Jethani, 2019/03/13 16:36:15]

Nit: We could call this `path` instead of `properties` as we have done in
`lib/content/snippets.js`. Your call.

[hub, 2019/03/14 10:28:04]

Done.

+    test.ok(properties.length >= 1);

[Manish Jethani, 2019/03/13 16:36:15]

This seems redundant. It is not possible for this check to fail.

[hub, 2019/03/14 10:28:04]

Done.

+
+    let exceptionCaught = false;
+    let value = 1;
+    try

[Manish Jethani, 2019/03/13 16:36:14]

Nit: Would be cleaner to read if a line was left before and after the try/catch.

[hub, 2019/03/14 10:28:05]

Done.

+    {
+      let obj = window;
+      while (properties.length > 1)
+        obj = obj[properties.shift()];
+      value = obj[properties.shift()];
+    }
+    catch (e)
+    {
+      if (properties.length == 0)

[Manish Jethani, 2019/03/14 10:58:12]

Will properties.length every be non-zero here?

+        exceptionCaught = true;
+    }
+    test.equal(exceptionCaught, result, `The property "${property}" didn't trigger and exception.`);

[Manish Jethani, 2019/03/13 16:36:15]

The message here doesn't make complete sense. What if `result` is `false` and an
exception _is_ triggered?

[hub, 2019/03/14 10:28:04]

Done.

+    test.equal(value, result ? 1 : undefined, `The value for "${property}" shouldn't have been read.`);

[Manish Jethani, 2019/03/13 16:36:15]

Same as above. Both of these cases assume `result` is `true`.

[hub, 2019/03/14 10:28:05]

Done.

+  }
+
+  await runSnippet(test, "abort-on-property-read", "abpTest");
+  await testProperty("abpTest");
+
+  window.abpTest2 = {prop1: "foo"};
+
+  await runSnippet(test, "abort-on-property-read", "abpTest2.prop1");
+  await testProperty("abpTest2.prop1");
+
+  // Test that we try to catch a property that don't exist yet.
+  await runSnippet(test, "abort-on-property-read", "abpTest3.prop1");
+  window.abpTest3 = {prop1: "foo"};
+  await testProperty("abpTest3.prop1");
+
+  // Test that other properties don't trigger.
+  await testProperty("abpTest3.prop2", false);
+
+  // Test overwriting the object with another object
+  window.foo = {bar: {}};
+  await runSnippet(test, "abort-on-property-read", "foo.bar.lambda");
+  await testProperty("foo.bar.lambda");
+  window.foo.bar = {};
+  await testProperty("foo.bar.lambda");
+
+  // Test if we start with a non-object
+  window.foo2 = 5;
+  await runSnippet(test, "abort-on-property-read", "foo2.bar2.lambda");
+  await testProperty("foo2.bar2.lambda");
+  window.foo2 = {};
+  await testProperty("foo2.bar2.lambda");
+
+  test.done();
+};
+