Core: Test all factory use cases from intro.js

There is a lot of logic in intro.js; now we test four cases:
1. (implicitly, via QUnit tests) A real browser with window being the global
2. Browserify where there are both global & window variables.
3. Node with jsdom where window is passed manually to the jQuery factory.
4. Pure Node with incorrect window passed; jQuery should throw then.

Previously the second & fourth case was not tested and the third was tested
in a way that interfered with the main test environment.

We now also test if in the Browserify case we're not creating a jQuery global
by default.

Fixes gh-2181
Closes gh-2234

5 files changed, 60 insertions, 36 deletions

diff --git a/build/tasks/lib/spawn_test.js b/build/tasks/lib/spawn_test.js
new file mode 100644
index 000000000..6c4596a3d
--- /dev/null
+++ b/build/tasks/lib/spawn_test.js
@@ -0,0 +1,16 @@
+/* jshint node: true */
+
+"use strict";
+
+// Run Node with provided parameters: the first one being the Grunt
+// done function and latter ones being files to be tested.
+// See the comment in ../node_smoke_tests.js for more information.
+module.exports = function spawnTest( done ) {
+	var testPaths = [].slice.call( arguments, 1 ),
+		spawn = require( "win-spawn" );
+
+	spawn( "node", testPaths, { stdio: "inherit" } )
+		.on( "close", function( code ) {
+			done( code === 0 );
+		} );
+} ;
diff --git a/build/tasks/node_smoke_test.js b/build/tasks/node_smoke_test.js
deleted file mode 100644
index f39872521..000000000
--- a/build/tasks/node_smoke_test.js
+++ /dev/null
@@ -1,16 +0,0 @@
-module.exports = function( grunt ) {
-
-	"use strict";
-
-	grunt.registerTask( "node_smoke_test", function() {
-	    var done = this.async();
-		require( "jsdom" ).env( "", function( errors, window ) {
-			if ( errors ) {
-				console.error( errors );
-				done( false );
-			}
-			require( "../.." )( window );
-			done();
-		});
-	});
-};
diff --git a/build/tasks/node_smoke_tests.js b/build/tasks/node_smoke_tests.js
new file mode 100644
index 000000000..2a741c57a
--- /dev/null
+++ b/build/tasks/node_smoke_tests.js
@@ -0,0 +1,31 @@
+module.exports = function( grunt ) {
+
+	"use strict";
+
+	var fs = require( "fs" ),
+		spawnTest = require( "./lib/spawn_test.js" ),
+		testsDir = "./test/node_smoke_tests/",
+		nodeSmokeTests = [];
+
+	// Fire up all tests defined in test/node_smoke_tests/*.js in spawned sub-processes.
+	// All the files under test/node_smoke_tests/*.js are supposed to exit with 0 code
+	// on success or another one on failure. Spawning in sub-processes is
+	// important so that the tests & the main process don't interfere with
+	// each other, e.g. so that they don't share the require cache.
+
+	fs.readdirSync( testsDir )
+		.filter( function( testFilePath ) {
+			return fs.statSync( testsDir + testFilePath ).isFile();
+		} )
+		.forEach( function( testFilePath ) {
+			var taskName = "node_" + testFilePath.replace( /\.js$/, "" );
+
+			grunt.registerTask( taskName, function() {
+				spawnTest( this.async(), "test/node_smoke_tests/" + testFilePath );
+			} );
+
+			nodeSmokeTests.push( taskName );
+		} );
+
+	grunt.registerTask( "node_smoke_tests", nodeSmokeTests );
+};
diff --git a/build/tasks/promises-aplus-tests.js b/build/tasks/promises-aplus-tests.js
deleted file mode 100644
index 458ae1be0..000000000
--- a/build/tasks/promises-aplus-tests.js
+++ /dev/null
@@ -1,20 +0,0 @@
-module.exports = function( grunt ) {
-
-	"use strict";
-
-	var spawn = require( "child_process" ).spawn;
-
-	grunt.registerTask( "promises-aplus-tests", function() {
-		var done = this.async();
-		spawn(
-			"node",
-			[
-				"./node_modules/.bin/promises-aplus-tests",
-				"test/promises-aplus-adapter.js"
-			],
-			{ stdio: "inherit" }
-		).on( "close", function( code ) {
-			done( code === 0 );
-		});
-	});
-};
diff --git a/build/tasks/promises_aplus_tests.js b/build/tasks/promises_aplus_tests.js
new file mode 100644
index 000000000..3e770a079
--- /dev/null
+++ b/build/tasks/promises_aplus_tests.js
@@ -0,0 +1,13 @@
+module.exports = function( grunt ) {
+
+	"use strict";
+
+	var spawnTest = require( "./lib/spawn_test.js" );
+
+	grunt.registerTask( "promises_aplus_tests", function() {
+		spawnTest( this.async(),
+			"./node_modules/.bin/promises-aplus-tests",
+			"test/promises_aplus_adapter.js"
+		);
+	} );
+};