Issue 6090 - Allow use of console to be seen during tests

test/_common.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 76 matching lines @@
 
       throw new Error(
         "Attempt to import unknown JavaScript module " + resource
       );
     },
     reportError(e) {}
   },
   console: {
     log: console.log.bind(console),
     error: console.error.bind(console)
   },

[Wladimir Palant, 2017/11/28 12:59:39]

Just remove console here, not overriding this global will do.

[hub, 2017/11/28 15:29:33]

Done in follow up patch

   navigator: {
   },
   onShutdown: {
     add() {}
   },
   URL
 };
 
 let knownModules = new Map();
 for (let dir of [path.join(__dirname, "stub-modules"),
@@ skipping 304 matching lines @@
     Cr,
     XMLHttpRequest,
     Date: {
       now: () => currentTime
     }
   };
 };
 
 console.warn = console.log;
 
-exports.maybeExpectError = function(msg, test)

[sergei, 2017/11/24 10:15:28]

What about calling it `silenceAssertionOutput`?

[sergei, 2017/11/24 13:49:13]

JIC, I also thought that we could want to actually test that there is such
output from time to time by enabling an additional flag, and in this case
something like expectAssertionOutput would make sense, but I doubt that we
should really test assertion messages. We still can do it technically but
basically we want to deliberately not show expected messages.

[hub, 2017/11/24 15:48:59]

Done.

[hub, 2017/11/24 15:48:59]

I thought about expecting the output but then I'd need to check this is a DEBUG
build, otherwise assert2() is a noop.

+exports.silenceAssertionOutput = function(test, msg)
 {
   let msgMatch = new RegExp(`^Error: ${msg}[\r\n]`);

[Wladimir Palant, 2017/11/28 12:59:40]

1) Inserting unescaped strings into a regular expression is a footgun (consider
dots or question marks). If anything, the regular expression should be used to
extract the message, then you should use regular string comparison.

2) Parsing string representation of errors isn't a good idea either, it can
change. You have an Error object here, just look at the `error.message`
property.

[hub, 2017/11/28 15:29:33]

Done in followup patch.
we only have a string at that level. We'd need to change the error reporting.
Since this is only in the test, I consider it to be a reasonable assumption.

   let errorHandler = globals.console.error;

[sergei, 2017/11/24 10:15:28]

I think it's OK taking into account that `console` is bound to `console.error`
and it's even in the same file.

[hub, 2017/11/24 15:48:59]

I'm missing a patch here where we actualle make console.log and console.error
work, I'll update with it.

   globals.console.error = s =>
   {
-    if (!msgMatch.test(s) && typeof errorHandler === "function")

[sergei, 2017/11/24 10:15:28]

I think we should not test the type of errorHandler because it would be better
to crash if it's not a function.

[hub, 2017/11/24 15:48:59]

Acknowledged.

+    if (!msgMatch.test(s))
       errorHandler(s);
   };
   try
   {
-    test();

[sergei, 2017/11/24 10:15:28]

IMO we should return the result of `test()` for the sake of simplicity.

[hub, 2017/11/24 15:48:59]

Acknowledged.

+    return test();
   }
   finally
   {
     globals.console.error = errorHandler;
   }
 };
 
 exports.setupRandomResult = function()
 {
   let randomResult = 0.5;
   Object.defineProperty(this, "randomResult", {
     get: () => randomResult,
     set: value => randomResult = value
   });
 
   return {
     Math: Object.create(Math, {
       random: {
         value: () => randomResult
       }
     })
   };
 };
 
 exports.unexpectedError = function(error)
 {
   console.error(error);
   this.ok(false, "Unexpected error: " + error);
 };