Add test for 'dev' argument

tests/e2e/dev_console.js

@@ -0,0 +1,52 @@
+const Application = require("spectron").Application;
+const path = require("path");
+const chai = require("chai");
+const chaiAsPromised = require("chai-as-promised");
+
+var electronPath = path.join(__dirname, "../../", "node_modules", ".bin", "electron");
+
+if (process.platform === "win32") {
+	electronPath += ".cmd";
+}
+
+var appPath = path.join(__dirname, "../../js/electron.js");
+
+var app = new Application({
+	path: electronPath
+});
+
+global.before(function () {
+	chai.should();
+	chai.use(chaiAsPromised);
+});
+
+describe("Argument 'dev'", function () {
+	this.timeout(10000);
+
+	before(function() {
+		// Set config sample for use in test
+		process.env.MM_CONFIG_FILE = "tests/configs/env.js";
+	});
+
+	afterEach(function (done) {
+		app.stop().then(function() { done(); });
+	});
+
+	it("should not open dev console when absent", function () {
+		app.args = [appPath];
+
+		return app.start().then(function() {
+			return app.client.waitUntilWindowLoaded()
+				.getWindowCount().should.eventually.equal(1);
+		});
+	});
+
+	it("should open dev console when provided", function () {
+		app.args = [appPath, 'dev'];
+
+		return app.start().then(function() {
+			return app.client.waitUntilWindowLoaded()
+				.getWindowCount().should.eventually.equal(2);
+		});
+	});
+});