Fix how QUnit.newMwEnvironment merges live and custom settings

[lhc/web/wiklou.git] / tests / qunit / data / testrunner.js

diff --git a/tests/qunit/data/testrunner.js b/tests/qunit/data/testrunner.js
index c89656d..77db213 100644 (file)
--- a/tests/qunit/data/testrunner.js
+++ b/tests/qunit/data/testrunner.js
@@ -109,12 +109,14 @@
                liveMessages = mw.messages.values;
 
                function freshConfigCopy( custom ) {
-                       // "deep=true" is important here.
-                       // Otherwise we just create a new object with values referring to live config.
-                       // e.g. mw.config.set( 'wgFileExtensions', [] ) would not effect liveConfig,
-                       // but mw.config.get( 'wgFileExtensions' ).push( 'png' ) would as the array
-                       // was passed by reference in $.extend's loop.
-                       return $.extend( /*deep=*/true, {}, liveConfig, custom );
+                       // Tests should mock all factors that directly influence the tested code.
+                       // For backwards compatibility though we set mw.config to a copy of the live config
+                       // and extend it with the (optionally) given custom settings for this test
+                       // (instead of starting blank with only the given custmo settings).
+                       // This is a shallow copy, so we don't end up with settings taking an array value
+                       // extended with the custom settings - setting a config property means you override it,
+                       // not extend it.
+                       return $.extend( {}, liveConfig, custom );
                }
 
                function freshMessagesCopy( custom ) {