Noissue - Allow identifying the element in case of error in test

test/browser/elemHideEmulation.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 37 matching lines @@
     window.setTimeout(resolve, delay);
   });
 }
 
 function unexpectedError(error)
 {
   console.error(error);
   this.ok(false, "Unexpected error: " + error);
 }
 
-function expectHidden(test, element)
+function expectHidden(test, element, id)
 {
-  test.equal(window.getComputedStyle(element).display, "none",
-             "The element's display property should be set to 'none'");
+  let elementId = id ? `: ${id}` : "";
+  test.equal(
+    window.getComputedStyle(element).display, "none",
+    `The element's display property should be set to 'none' ${elementId}`);

[kzar, 2018/03/19 16:55:20]

Please can you improve the message, like "The element with ID 'foo'...".

[hub, 2018/03/20 14:40:26]

Done.

 }
 
-function expectVisible(test, element)
+function expectVisible(test, element, id)
 {
-  test.notEqual(window.getComputedStyle(element).display, "none",
-                "The element's display property should not be set to 'none'");
+  let elementId = id ? `: ${id}` : "";
+  test.notEqual(
+    window.getComputedStyle(element).display, "none",
+    `The element's display property should not be set to 'none' ${elementId}`);
 }
 
 function findUniqueId()
 {
   let id = "elemHideEmulationTest-" + Math.floor(Math.random() * 10000);
   if (!testDocument.getElementById(id))
     return id;
   return findUniqueId();
 }
 
@@ skipping 275 matching lines @@
   }).catch(unexpectedError.bind(test)).then(() => test.done());
 };
 
 function compareExpectations(test, elems, expectations)
 {
   for (let elem in expectations)
   {
     if (elems[elem])
     {
       if (expectations[elem])
-        expectVisible(test, elems[elem]);
+        expectVisible(test, elems[elem], elem);
       else
-        expectHidden(test, elems[elem]);
+        expectHidden(test, elems[elem], elem);
     }
   }
 }
 
 function runTestPseudoClassHasSelectorWithHasAndWithSuffixSibling(test, selector, expectations)
 {
   testDocument.body.innerHTML = `<div id="parent">
       <div id="middle">
         <div id="middle1"><div id="inside" class="inside"></div></div>
       </div>
@@ skipping 306 matching lines @@
     expectVisible(test, child2);
     return timeout(REFRESH_INTERVAL);
   }).then(() =>
   {
     expectHidden(test, parent);
     expectVisible(test, child);
     expectHidden(test, sibling);
     expectVisible(test, child2);
   }).catch(unexpectedError.bind(test)).then(() => test.done());
 };