Add Jest for JavaScript testing

frontend/tests/init.test.js

@@ -0,0 +1,20 @@
+import {test, expect} from "@jest/globals";
+import "./inittests";
+
+test("Checks for valid mock server timezone (serverTZ)", () => {
+	expect(isNaN(serverTZ)).toBe(false);
+});
+
+test("Checks mock themes to make sure the default one (defaultStyle) exists and is pipes.css", () => {
+	let styleName = "";
+	for(const style of styles) {
+		if(style.Filename == defaultStyle) {
+			styleName = style.Name;
+		}
+	}
+	expect(styleName).toBe("Pipes");
+});
+
+test("tests mock webroot, should be /", () => {
+	expect(webroot).toBe("/");
+});

frontend/tests/inittests.js

@@ -0,0 +1,16 @@
+// mock variables the browser would normally get from {webroot}js/consts.js
+global.styles=[
+	{Name: "Pipes", Filename: "pipes.css"},
+	{Name: "BunkerChan", Filename: "bunkerchan.css"},
+	{Name: "Burichan", Filename: "burichan.css"},
+	{Name: "Clear", Filename: "clear.css"},
+	{Name: "Dark", Filename: "dark.css"},
+	{Name: "Photon", Filename: "photon.css"},
+	{Name: "Yotsuba", Filename: "yotsuba.css"},
+	{Name: "Yotsuba B", Filename: "yotsubab.css"},
+	{Name: "Windows 9x", Filename: "win9x.css"}
+];
+
+global.defaultStyle = "pipes.css";
+global.webroot = "/";
+global.serverTZ = -8;