Build: Run Karma tests sequentially in separate processes + other improvements

Sizzle hasn't been able to finish all its unit tests successfully for a long time. This commit attempts to make it work again (at least most of the time).

Summary of the changes:
1. A new "karma-tests" task is created; it runs tests in various browser sets
but does it sequentially in separate processes to avoid Karma bugs that cause
browsers from previous sets to somehow still be waited on during subsequent
runs, failing the build.
2. Upgrade tested browsers.
3. Run iOS tests at the end (as it fails more often than other browsers).
4. Use real iOS 10.3 device in Karma.

We can't upgrade Karma as the latest version (`4.2.0`) hangs in IE 7 (IE 8 seems to work fine there).

Closes gh-455

Author: mgol

.eslintrc-node.json

@@ -4,7 +4,7 @@
 	"extends": "jquery",
 
 	"parserOptions": {
-		"ecmaVersion": 2017
+		"ecmaVersion": 2018
 	},
 
 	"env": {

Gruntfile.js

@@ -32,16 +32,16 @@ module.exports = function( grunt ) {
 
 		browsers.desktop = [
 			"bs_chrome-45", // shares V8 with Node.js 4 LTS
-			"bs_chrome-70", "bs_chrome-71",
+			"bs_chrome-75", "bs_chrome-76",
 
 			"bs_firefox-52", "bs_firefox-60", // Firefox ESR
-			"bs_firefox-63", "bs_firefox-64",
+			"bs_firefox-67", "bs_firefox-68",
 
 			"bs_edge-17", "bs_edge-18",
 
 			"bs_ie-9", "bs_ie-10", "bs_ie-11",
 
-			"bs_opera-56", "bs_opera-57",
+			"bs_opera-60", "bs_opera-62",
 
 			// Real Safari 6.1 and 7.0 are not available
 			"bs_safari-6.0", "bs_safari-8.0", "bs_safari-9.1", "bs_safari-10.1",
@@ -258,19 +258,9 @@ module.exports = function( grunt ) {
 	grunt.registerTask( "lint", [ "jsonlint", "eslint:dev", "eslint:dist" ] );
 	grunt.registerTask( "start", [ "karma:watch:start", "watch" ] );
 
-	// Execute tests all browsers in sequential way,
-	// so slow connections would not affect other runs
-	grunt.registerTask( "tests", isBrowserStack ? [
-		"karma:phantom", "karma:desktop",
-
-		"karma:ios",
-
-		"karma:oldIe", "karma:oldFirefox", "karma:oldChrome",
-		"karma:oldSafari", "karma:oldOpera"
-
-		// See #314 :-(
-		// "karma:android", "karma:oldAndroid"
-	] : "karma:phantom" );
+	grunt.registerTask( "tests", [
+		`karma-tests:${ isBrowserStack ? "browserstack" : "" }`
+	] );
 
 	grunt.registerTask( "build", [
 		"jsonlint",

tasks/karma-tests.js

@@ -0,0 +1,52 @@
+"use strict";
+
+const spawn = require( "child_process" ).spawn;
+
+module.exports = function( grunt ) {
+
+	// The task runs tests in various browser sets but does it sequentially in
+	// separate processes to avoid Karma bugs that cause browsers from previous
+	// sets to somehow still be waited on during subsequent runs, failing the build.
+	grunt.registerTask( "karma-tests", "Run unit tests sequentially",
+		async function( isBrowserStack ) {
+			const done = this.async();
+
+			const tasks = isBrowserStack ? [
+				"karma:phantom", "karma:desktop",
+
+				"karma:oldIe", "karma:oldFirefox", "karma:oldChrome",
+				"karma:oldSafari", "karma:oldOpera",
+
+				"karma:ios"
+
+				// See #314 :-(
+				// "karma:android", "karma:oldAndroid"
+			] : [ "karma:phantom" ];
+
+			for ( let task of tasks ) {
+				const command = `grunt ${ task }`;
+				grunt.log.writeln( `Running task ${ task } in a subprocess...` );
+
+				await new Promise( ( resolve, reject ) => {
+					const ret = spawn( command, {
+						shell: true,
+						stdio: "inherit"
+					} );
+
+					ret.on( "close", ( code ) => {
+						if ( code === 0 ) {
+							resolve();
+						} else {
+							const message = `Error code ${ code } during command: ${ command }`;
+							console.error( message );
+							reject( new Error( message ) );
+							done( false );
+						}
+					} );
+				} );
+			}
+
+			done();
+		}
+	);
+};

test/karma/launchers.js

@@ -22,17 +22,17 @@ module.exports = {
 		os: "OS X",
 		os_version: "High Sierra"
 	},
-	"bs_firefox-63": {
+	"bs_firefox-67": {
 		base: "BrowserStack",
 		browser: "firefox",
-		browser_version: "63.0",
+		browser_version: "67.0",
 		os: "OS X",
 		os_version: "Mojave"
 	},
-	"bs_firefox-64": {
+	"bs_firefox-68": {
 		base: "BrowserStack",
 		browser: "firefox",
-		browser_version: "64.0",
+		browser_version: "68.0",
 		os: "OS X",
 		os_version: "Mojave"
 	},
@@ -51,17 +51,17 @@ module.exports = {
 		os: "OS X",
 		os_version: "Sierra"
 	},
-	"bs_chrome-70": {
+	"bs_chrome-75": {
 		base: "BrowserStack",
 		browser: "chrome",
-		browser_version: "70.0",
+		browser_version: "75.0",
 		os: "OS X",
 		os_version: "Mojave"
 	},
-	"bs_chrome-71": {
+	"bs_chrome-76": {
 		base: "BrowserStack",
 		browser: "chrome",
-		browser_version: "71.0",
+		browser_version: "76.0",
 		os: "OS X",
 		os_version: "Mojave"
 	},
@@ -138,17 +138,17 @@ module.exports = {
 		os: "Windows",
 		os_version: "7"
 	},
-	"bs_opera-56": {
+	"bs_opera-60": {
 		base: "BrowserStack",
 		browser: "opera",
-		browser_version: "56.0",
+		browser_version: "60.0",
 		os: "OS X",
 		os_version: "Mojave"
 	},
-	"bs_opera-57": {
+	"bs_opera-62": {
 		base: "BrowserStack",
 		browser: "opera",
-		browser_version: "57.0",
+		browser_version: "62.0",
 		os: "OS X",
 		os_version: "Mojave"
 	},
@@ -251,7 +251,8 @@ module.exports = {
 		base: "BrowserStack",
 		device: "iPhone 7",
 		os: "ios",
-		os_version: "10.3"
+		os_version: "10.3",
+		real_mobile: true
 	},
 	"bs_ios-11.4": {
 		base: "BrowserStack",