From 705a7336520c2658112c390e63d5f5dc8bb336b1 Mon Sep 17 00:00:00 2001
From: Timo Tijhof <krinklemail@gmail.com>
Date: Wed, 28 Sep 2016 19:12:52 +0100
Subject: [PATCH] mw.loader: Add tests for mw.loader StringSet fallback

Change-Id: Ia00d793f0332531b5afa006fe8453e2e733d40ba
---
 resources/src/mediawiki/mediawiki.js          | 44 ++++++++++++-------
 .../mediawiki/mediawiki.loader.test.js        | 38 +++++++++++++++-
 2 files changed, 64 insertions(+), 18 deletions(-)

diff --git a/resources/src/mediawiki/mediawiki.js b/resources/src/mediawiki/mediawiki.js
index 33f146b9d4..c2cee7ec6f 100644
--- a/resources/src/mediawiki/mediawiki.js
+++ b/resources/src/mediawiki/mediawiki.js
@@ -52,23 +52,25 @@
 		/* eslint-enable no-bitwise */
 	}
 
-	// <https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Set>
-	StringSet = window.Set || ( function () {
-		/**
-		 * @private
-		 * @class
-		 */
-		function StringSet() {
-			this.set = {};
-		}
-		StringSet.prototype.add = function ( value ) {
-			this.set[ value ] = true;
-		};
-		StringSet.prototype.has = function ( value ) {
-			return hasOwn.call( this.set, value );
-		};
-		return StringSet;
-	}() );
+	function defineFallbacks() {
+		// <https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Set>
+		StringSet = window.Set || ( function () {
+			/**
+			 * @private
+			 * @class
+			 */
+			function StringSet() {
+				this.set = {};
+			}
+			StringSet.prototype.add = function ( value ) {
+				this.set[ value ] = true;
+			};
+			StringSet.prototype.has = function ( value ) {
+				return hasOwn.call( this.set, value );
+			};
+			return StringSet;
+		}() );
+	}
 
 	/**
 	 * Create an object that can be read from or written to via methods that allow
@@ -413,6 +415,8 @@
 		}
 	};
 
+	defineFallbacks();
+
 	/* eslint-disable no-console */
 	log = ( function () {
 		// Also update the restoration of methods in mediawiki.log.js
@@ -508,6 +512,12 @@
 	 * @class mw
 	 */
 	mw = {
+		redefineFallbacksForTest: function () {
+			if ( !window.QUnit ) {
+				throw new Error( 'Reset not allowed outside unit tests' );
+			}
+			defineFallbacks();
+		},
 
 		/**
 		 * Get the current time, measured in milliseconds since January 1, 1970 (UTC).
diff --git a/tests/qunit/suites/resources/mediawiki/mediawiki.loader.test.js b/tests/qunit/suites/resources/mediawiki/mediawiki.loader.test.js
index 6f9af7677a..477b04dcc9 100644
--- a/tests/qunit/suites/resources/mediawiki/mediawiki.loader.test.js
+++ b/tests/qunit/suites/resources/mediawiki/mediawiki.loader.test.js
@@ -5,6 +5,11 @@
 		},
 		teardown: function () {
 			mw.loader.store.enabled = false;
+			// Teardown for StringSet shim test
+			if ( this.nativeSet ) {
+				window.Set = this.nativeSet;
+				mw.redefineFallbacksForTest();
+			}
 		}
 	} ) );
 
@@ -133,7 +138,8 @@
 		} );
 	} );
 
-	QUnit.test( '.using() Error: Circular dependency', function ( assert ) {
+	// Covers mw.loader#sortDependencies (with native Set if available)
+	QUnit.test( '.using() Error: Circular dependency [StringSet default]', function ( assert ) {
 		var done = assert.async();
 
 		mw.loader.register( [
@@ -152,6 +158,36 @@
 		.always( done );
 	} );
 
+	// @covers mw.loader#sortDependencies (with fallback shim)
+	QUnit.test( '.using() Error: Circular dependency [StringSet shim]', function ( assert ) {
+		var done = assert.async();
+
+		if ( !window.Set ) {
+			assert.expect( 0 );
+			done();
+			return;
+		}
+
+		this.nativeSet = window.Set;
+		window.Set = undefined;
+		mw.redefineFallbacksForTest();
+
+		mw.loader.register( [
+			[ 'test.shim.circle1', '0', [ 'test.shim.circle2' ] ],
+			[ 'test.shim.circle2', '0', [ 'test.shim.circle3' ] ],
+			[ 'test.shim.circle3', '0', [ 'test.shim.circle1' ] ]
+		] );
+		mw.loader.using( 'test.shim.circle3' ).then(
+			function done() {
+				assert.ok( false, 'Unexpected resolution, expected error.' );
+			},
+			function fail( e ) {
+				assert.ok( /Circular/.test( String( e ) ), 'Detect circular dependency' );
+			}
+		)
+		.always( done );
+	} );
+
 	QUnit.test( '.load() - Error: Circular dependency', function ( assert ) {
 		mw.loader.register( [
 			[ 'test.circleA', '0', [ 'test.circleB' ] ],
-- 
2.20.1