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

test/browser/snippets.js

 /*
  * 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
@@ skipping 16 matching lines @@
   }
 };
 
 async function runSnippet(test, snippetName, ...args)
 {
   let snippet = library[snippetName];
 
   test.ok(snippet);
 
   snippet(...args);
+
+  // 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.
   await timeout(100);
 }
 
 exports.testAbortOnPropertyReadSnippet = async function(test)
 {
-  window.abpTest = "foo";
-
-  function testProperty(property, result = true)
+  function testProperty(property, result = true, errorName = "ReferenceError")
   {
     let path = property.split(".");
 
     let exceptionCaught = false;
     let value = 1;
 
     try
     {
       let obj = window;
       while (path.length > 1)
         obj = obj[path.shift()];
       value = obj[path.shift()];
     }
     catch (e)
     {
-      if (path.length == 0)
-        exceptionCaught = true;
+      test.equal(e.name, errorName);
+      exceptionCaught = true;
     }
 
-    test.equal(exceptionCaught, result, `The property "${property}" ${result ? "shouldn't" : "should"} trigger an exception.`);
-    test.equal(value, result ? 1 : undefined, `The value for "${property}" ${result ? "shouldn't" : "should"} have been read.`);
+    test.equal(
+      exceptionCaught,
+      result,
+      `The property "${property}" ${result ? "should" : "shouldn't"} trigger an exception.`
+    );
+    test.equal(
+      value,
+      result ? 1 : undefined,
+      `The value for "${property}" ${result ? "shouldn't" : "should"} have been read.`
+    );
   }
 
+  window.abpTest = "fortytwo";
   await runSnippet(test, "abort-on-property-read", "abpTest");
   testProperty("abpTest");
 
-  window.abpTest2 = {prop1: "foo"};
-
+  window.abpTest2 = {prop1: "fortytwo"};
   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.
+  // Test that we try to catch a property that doesn't exist yet.
   await runSnippet(test, "abort-on-property-read", "abpTest3.prop1");
-  window.abpTest3 = {prop1: "foo"};
+  window.abpTest3 = {prop1: "fortytwo"};
   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 overwriting the object with another object.
+  window.abpTest4 = {prop3: {}};
+  await runSnippet(test, "abort-on-property-read", "abpTest4.prop3.foo");
+  testProperty("abpTest4.prop3.foo");
+  window.abpTest4.prop3 = {};
+  testProperty("abpTest4.prop3.foo");
 
-  // Test if we start with a non-object
-  window.foo2 = 5;

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

This test just happens to pass because `testProperty()` throws a `TypeError` at
just the right point. It's not the error thrown by the snippet, it's just that
`bar2` is `undefined` so you can't access `lambda` anyway. It's a wrong test.

After running the snippet, we should set `foo2` and `foo2.bar2` to objects.

[Manish Jethani, 2019/03/19 07:43:59]

What about this?

[Manish Jethani, 2019/03/19 17:38:23]

Looks good now except for this. As I said, it just happens to work by accident.

[hub, 2019/03/19 18:24:46]

Sorry I totally missed that one.

Fixed.

-  await runSnippet(test, "abort-on-property-read", "foo2.bar2.lambda");
-  testProperty("foo2.bar2.lambda");
-  window.foo2 = {};
-  testProperty("foo2.bar2.lambda");
+  // Test if we start with a non-object.
+  window.abpTest5 = 42;
+  await runSnippet(test, "abort-on-property-read", "abpTest5.prop4.bar");
+
+  testProperty("abpTest5.prop4.bar", true, "TypeError");
+
+  window.abpTest5 = {prop4: 42};
+  testProperty("abpTest5.prop4.bar", false);
+  window.abpTest5 = {prop4: {}};
+  testProperty("abpTest5.prop4.bar");
 
   test.done();
 };