Issue 6853 - Add unit tests for quirks in snippet script parsing

test/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 170 matching lines @@
                     [["f\ud83d\ude42\ud83d\ude42", "b\ud83d\ude02r"]]);
   checkParsedScript("Script with no-op commands", "foo; ;;; ;  ; bar 1",
                     [["foo"], ["bar", "1"]]);
   checkParsedScript("Script with blank argument in the middle", "foo '' Hello",
                     [["foo", "", "Hello"]]);
   checkParsedScript("Script with blank argument at the end", "foo Hello ''",
                     [["foo", "Hello", ""]]);
   checkParsedScript("Script with consecutive blank arguments", "foo '' ''",
                     [["foo", "", ""]]);
 
+  // Undocumented quirks (#6853).
+  checkParsedScript("Script with quotes within an argument", "foo Hello''world",
+                    [["foo", "Helloworld"]]);
+  checkParsedScript("Script with quotes within an argument containing whitespace",
+                    "foo Hello' 'world",
+                    [["foo", "Hello world"]]);
+  checkParsedScript("Script with quotes within an argument containing non-whitespace",
+                    "foo Hello','world",
+                    [["foo", "Hello,world"]]);
+  checkParsedScript("Script with quotes within an argument containing whitespace and non-whitespace",
+                    "foo Hello', 'world",
+                    [["foo", "Hello, world"]]);
+  checkParsedScript("Script with opening quote at the beginning of an argument",
+                    "foo 'Hello, 'world",
+                    [["foo", "Hello, world"]]);
+  checkParsedScript("Script with closing quote at the end of an argument",
+                    "foo Hello,' world'",
+                    [["foo", "Hello, world"]]);
+
+  checkParsedScript("Script with closing quote missing", "foo 'Hello, world",
+                    []);
+  checkParsedScript("Script with closing quote missing in last command",
+                    "foo Hello; bar 'How are you?",
+                    [["foo", "Hello"]]);
+  checkParsedScript("Script ending with a backslash",
+                    "foo Hello; bar 'How are you?' \\",
+                    [["foo", "Hello"]]);
+
   test.done();
 };
 
 exports.testScriptCompilation = function(test)
 {
   let libraries = [
     `
       let foo = 0;
 
       exports.setFoo = function(value)
@@ skipping 52 matching lines @@
   // between executions. In the example below, assertFoo does not find 456 but
   // it doesn't find 123 either. It's the initial value 0.
   new Function(
     compileScript("setFoo 456; assertFoo 0", [
       ...libraries, "let foo = 1; exports.setFoo = value => { foo = value; };"
     ])
   )();
 
   test.done();
 };