Tests: Add a new esmodules flag, remove the raw one

Migrating from AMD to ES modules in gh-343 made the `raw` testing mode break as
it relied on loading raw source files. This change removes the `raw` mode in
favor of the new `esmodules` one.

Setup is different than in jQuery as jQuery uses AMD to load tests and Migrate
just loads test files directly.

When Migrate is loaded via its source ES modules, test files are loaded as
modules as well. This is necessary as module scripts behave as if loaded with
the `defer` attribute so tests need to be deferred as well.

Iframe tests are skipped in `esmodules` mode as their setup is incompatible
with the above considerations.

In addition to the above, Karma tests now also run in esmodules mode for easier
verification this mode is not broken by PRs.

Closes gh-468
Ref gh-343

Author: mgol

Gruntfile.js

@@ -8,28 +8,43 @@ module.exports = function( grunt ) {
 
 	const oldNode = /^v10\./.test( process.version );
 
-	const karmaFilesExceptJQuery = [
+	const karmaQunitConfig = {
+		showUI: true,
+		testTimeout: 5000,
+
+		// We're running `QUnit.start()` ourselves in
+		// test/data/qunit-start.js
+		autostart: false
+	};
+
+	const karmaFilesExceptJQueryAndMigrate = [
+
+		// In esmodules mode only object entries of this array with `type: "js"`
+		// get the `type: "module"` tweak. npo is incompatible with being loaded as
+		// a module so leverage this hack to prevent loading it in this way.
 		"external/npo/npo.js",
-		"dist/jquery-migrate.min.js",
-		"test/data/compareVersions.js",
-
-		"test/data/testinit.js",
-		"test/data/test-utils.js",
-		"test/unit/migrate.js",
-		"test/unit/jquery/core.js",
-		"test/unit/jquery/ajax.js",
-		"test/unit/jquery/attributes.js",
-		"test/unit/jquery/css.js",
-		"test/unit/jquery/data.js",
-		"test/unit/jquery/deferred.js",
-		"test/unit/jquery/effects.js",
-		"test/unit/jquery/event.js",
-		"test/unit/jquery/manipulation.js",
-		"test/unit/jquery/offset.js",
-		"test/unit/jquery/serialize.js",
-		"test/unit/jquery/traversing.js",
-
-		{ pattern: "dist/jquery-migrate.js", included: false, served: true },
+
+		{ pattern: "test/data/compareVersions.js", type: "js", nocache: true },
+
+		{ pattern: "test/data/testinit.js", type: "js", nocache: true },
+		{ pattern: "test/data/test-utils.js", type: "js", nocache: true },
+		{ pattern: "test/unit/migrate.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/core.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/ajax.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/attributes.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/css.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/data.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/deferred.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/effects.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/event.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/manipulation.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/offset.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/serialize.js", type: "js", nocache: true },
+		{ pattern: "test/unit/jquery/traversing.js", type: "js", nocache: true },
+
+		{ pattern: "test/data/qunit-start.js", type: "js", nocache: true },
+
+		{ pattern: "dist/jquery-migrate.js", included: false, served: true, nocache: true },
 		{ pattern: "test/**/*.@(js|json|css|jpg|html|xml)", included: false, served: true }
 	];
 
@@ -182,14 +197,12 @@ module.exports = function( grunt ) {
 				frameworks: [ "qunit" ],
 				files: [
 					"https://releases.jquery.com/git/jquery-3.x-git.min.js",
-					...karmaFilesExceptJQuery
+					"dist/jquery-migrate.min.js",
+					...karmaFilesExceptJQueryAndMigrate
 				],
 				client: {
 					clearContext: false,
-					qunit: {
-						showUI: true,
-						testTimeout: 5000
-					}
+					qunit: karmaQunitConfig
 				},
 				reporters: [ "dots" ],
 				autoWatch: false,
@@ -207,11 +220,51 @@ module.exports = function( grunt ) {
 				options: {
 					files: [
 						"https://releases.jquery.com/git/jquery-3.x-git.slim.min.js",
-						...karmaFilesExceptJQuery
+						"dist/jquery-migrate.min.js",
+						...karmaFilesExceptJQueryAndMigrate
 					]
 				}
 			},
 
+			esmodules: {
+				browsers: [ "ChromeHeadless", "FirefoxHeadless" ],
+				options: {
+					files: [
+						"https://releases.jquery.com/git/jquery-3.x-git.slim.min.js",
+						{ pattern: "src/migrate.js", type: "module" },
+
+						// Silence console warnings to avoid flooding the console.
+						{ pattern: "src/migratemute.js", type: "module" },
+
+						// Only object entries with `type: "js"` get
+						// the `type: "module"` tweak.
+						...karmaFilesExceptJQueryAndMigrate.map( file => {
+							if ( file && typeof file === "object" && file.type === "js" ) {
+								return {
+									...file,
+									type: "module"
+								};
+							} else {
+								return file;
+							}
+						} ),
+
+						{
+							pattern: "src/**",
+							included: false,
+							type: "module",
+							served: true
+						}
+					],
+					client: {
+						qunit: {
+							...karmaQunitConfig,
+							plugin: "esmodules"
+						}
+					}
+				}
+			},
+
 			// To debug tests with Karma:
 			// 1. Run 'grunt karma:chrome-debug' or 'grunt karma:firefox-debug'
 			//    (any karma subtask that has singleRun=false)
@@ -247,7 +300,8 @@ module.exports = function( grunt ) {
 	// Just an alias
 	grunt.registerTask( "test", [
 		"karma:main",
-		"karma:jquery-slim"
+		"karma:jquery-slim",
+		"karma:esmodules"
 	] );
 
 	grunt.registerTask( "lint", [

package-lock.json

@@ -48,7 +48,7 @@
 		"karma-qunit": "4.1.2",
 		"load-grunt-tasks": "5.1.0",
 		"native-promise-only": "0.8.1",
-		"qunit": "2.18.0",
+		"qunit": "2.19.1",
 		"rollup": "2.70.1",
 		"testswarm": "1.1.2"
 	},

package.json

@@ -1,5 +1,5 @@
 // Returns 0 if v1 == v2, -1 if v1 < v2, 1 if v1 > v2
-function compareVersions( v1, v2 ) {
+window.compareVersions = function compareVersions( v1, v2 ) {
 	var i,
 		rVersionParts = /^(\d+)\.(\d+)\.(\d+)/,
 		v1p = rVersionParts.exec( v1 ) || [ ],
@@ -14,8 +14,8 @@ function compareVersions( v1, v2 ) {
 		}
 	}
 	return 0;
-}
+};
 
-function jQueryVersionSince( version ) {
+window.jQueryVersionSince = function jQueryVersionSince( version ) {
 	return compareVersions( jQuery.fn.jquery, version ) >= 0;
-}
+};

test/data/compareVersions.js

@@ -0,0 +1 @@
+QUnit.start();

test/data/qunit-start.js

@@ -1,6 +1,6 @@
 /* exported expectWarning, expectNoWarning */
 
-function expectWarning( assert, name, expected, fn ) {
+window.expectWarning = function expectWarning( assert, name, expected, fn ) {
 	var result;
 	if ( !fn ) {
 		fn = expected;
@@ -41,10 +41,10 @@ function expectWarning( assert, name, expected, fn ) {
 		check();
 		return Promise.resolve();
 	}
-}
+};
 
-function expectNoWarning( assert, name, expected, fn ) {
+window.expectNoWarning = function expectNoWarning( assert, name, expected, fn ) {
 
 	// Expected is present only for signature compatibility with expectWarning
 	return expectWarning( assert, name, 0, fn || expected );
-}
+};