Build: Don't install jsdom 3 on Node.js 0.10 & 0.12 by default

jsdom 3 requires Python & Visual Studio on Windows which is a significant
barrier to contributors. Newer jsdom versions don't require pre-compiling
but work only on io.js. This commit installs the new jsdom everywhere (it
does install in old Node.js, it just won't work) and executes Node-related
tests only on newer Nodes or if a working jsdom version is installed. The
latter can be achieved by running the `old_jsdom` task.

Node.js is merging with io.js soon so this will become a smaller problem over
time.

One drawback is our Jenkins setup runs on Node 0.10 so it won't be running
Node tests anymore. We have Travis set up on io.js, though so all PRs
have those tests run. When the new LTS Node.js arrives (as it soon merges
with io.js) we should update our Jenkins infrastructure so that it runs on this
new version.

Fixes jquerygh-2519
Closes jquerygh-2526

Gruntfile.js

@@ -14,7 +14,17 @@ module.exports = function( grunt ) {
 	var fs = require( "fs" ),
 		stripJSONComments = require( "strip-json-comments" ),
 		gzip = require( "gzip-js" ),
-		srcHintOptions = readOptionalJSON( "src/.jshintrc" );
+		srcHintOptions = readOptionalJSON( "src/.jshintrc" ),
+		newNode = !/^v0/.test( process.version ),
+		// Allow to skip jsdom-related tests in Node.js < 1.0.0
+		runJsdomTests = newNode || ( function() {
+			try {
+				require( "jsdom" );
+				return true;
+			} catch ( e ) {
+				return false;
+			}
+		} )();
 
 	// The concatenated file won't pass onevar
 	// But our modules can
@@ -172,9 +182,14 @@ module.exports = function( grunt ) {
 
 	grunt.registerTask( "lint", [ "jsonlint", "jshint", "jscs" ] );
 
-	grunt.registerTask( "test_fast", [ "node_smoke_tests" ] );
+	// Don't run Node-related tests in Node.js < 1.0.0 as they require an old
+	// jsdom version that needs compiling, making it harder for people to compile
+	// jQuery on Windows. (see gh-2519)
+	grunt.registerTask( "test_fast", runJsdomTests ? [ "node_smoke_tests" ] : []);
 
-	grunt.registerTask( "test", [ "test_fast", "promises_aplus_tests" ] );
+	grunt.registerTask( "test", [ "test_fast" ].concat(
+		runJsdomTests ? [ "promises_aplus_tests" ] : []
+	) );
 
 	// Short list as a high frequency watch task
 	grunt.registerTask( "dev", [ "build:*:*", "lint", "uglify", "remove_map_comment", "dist:*" ] );

build/tasks/install_old_jsdom.js

@@ -0,0 +1,20 @@
+module.exports = function( grunt ) {
+
+	"use strict";
+
+	// Run this task to run jsdom-related tests on Node.js < 1.0.0.
+	grunt.registerTask( "old_jsdom", function() {
+		if ( !/^v0/.test( process.version ) ) {
+			console.warn( "The old_jsdom task doesn\'t need to be run in io.js or new Node.js" );
+			return;
+		}
+
+		// Use npm on the command-line
+		// There is no local npm
+		grunt.util.spawn( {
+			cmd: "npm",
+			args: [ "install", "jsdom@3" ],
+			opts: { stdio: "inherit" }
+		}, this.async() );
+	});
+};

build/tasks/node_smoke_tests.js

@@ -5,7 +5,7 @@ module.exports = function( grunt ) {
 	var fs = require( "fs" ),
 		spawnTest = require( "./lib/spawn_test.js" ),
 		testsDir = "./test/node_smoke_tests/",
-		nodeSmokeTests = [ "jsdom", "babel:nodeSmokeTests" ];
+		nodeSmokeTests = [ "babel: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

package.json

@@ -39,6 +39,7 @@
     "grunt-jsonlint": "1.0.4",
     "grunt-npmcopy": "0.1.0",
     "gzip-js": "0.3.2",
+    "jsdom": "5.6.1",
     "load-grunt-tasks": "1.0.0",
     "native-promise-only": "0.7.8-a",
     "promises-aplus-tests": "2.1.0",
@@ -51,10 +52,6 @@
     "testswarm": "1.1.0",
     "win-spawn": "2.0.0"
   },
-  "jsdomVersions": {
-    "node": "3.1.2",
-    "iojs": "5.3.0"
-  },
   "scripts": {
     "build": "npm install && grunt",
     "start": "grunt watch",