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 +1,100 @@
+/*
+ * 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);
+}
+
+exports.testAbortOnPropertyReadSnippet = async function(test)
+{
+  window.abpTest = "foo";
+
+  function testProperty(property, result = true)
+  {
+    let path = property.split(".");
+
+    let exceptionCaught = false;
+    let value = 1;
+
+    try
+    {
+      let obj = window;

[Manish Jethani, 2019/03/14 10:58:13]

What about just doing it exactly like in `lib/content/snippets.js`?

  let object = window;
  let path = api.split(".");
  let name = path.pop();

  for (let node of path)
    object = object[node];

  value = object[name];

[hub, 2019/03/14 12:32:55]

I don't think it really matters either way.

[Manish Jethani, 2019/03/14 16:56:23]

Alright.

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

[Manish Jethani, 2019/03/14 10:58:13]

Will `path.length` ever be non-zero here?

[hub, 2019/03/14 12:32:55]

if any other exception, it could.

[Manish Jethani, 2019/03/14 16:56:22]

And why would there be any other exception? Can you give an example? It seems
unnecessary to me.

[hub, 2019/03/14 22:22:11]

it's gone then.

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

[Manish Jethani, 2019/03/14 10:58:13]

Nit: We could use "should" here for consistency: "The property ${property}
${result ? "should" : "shouldn't"} have triggered an exception."

[hub, 2019/03/14 12:32:55]

Done.

[Manish Jethani, 2019/03/14 16:56:23]

"should" should be first, then "shouldn't".

[hub, 2019/03/14 22:22:11]

my bad, fixed.

+    test.equal(value, result ? 1 : undefined, `The value for "${property}" ${result ? "shouldn't" : "should"} have been read.`);
+  }
+
+  await runSnippet(test, "abort-on-property-read", "abpTest");
+  testProperty("abpTest");
+
+  window.abpTest2 = {prop1: "foo"};
+
+  await runSnippet(test, "abort-on-property-read", "abpTest2.prop1");
+  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"};
+  testProperty("abpTest3.prop1");
+
+  // Test that other properties don't trigger.
+  testProperty("abpTest3.prop2", false);
+
+  // Test overwriting the object with another object
+  window.foo = {bar: {}};
+  await runSnippet(test, "abort-on-property-read", "foo.bar.lambda");
+  testProperty("foo.bar.lambda");
+  window.foo.bar = {};
+  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");
+  testProperty("foo2.bar2.lambda");
+  window.foo2 = {};
+  testProperty("foo2.bar2.lambda");
+
+  test.done();
+};
+

[Manish Jethani, 2019/03/14 10:58:13]

Unnecessary blank line at the end.

[hub, 2019/03/14 12:32:55]

Done.