Added frontend tests

public/js-source/test/SomeModule.ts

@@ -0,0 +1,57 @@
+import {describe, it} from 'mocha';
+import {expect} from 'chai';
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore
+import * as fetchMock from 'fetch-mock';
+import {getUserName} from '../src/SomeModule';
+import {setConfig, UserInfo} from '../src/utils/utils';
+
+describe('frontend:SomeModule', () => {
+	const CONFIG = {EXTERNAL_BASE_URL: "http://demo.url"};
+	before(() => {
+		setConfig(CONFIG);
+		fetchMock.config.overwriteRoutes = true;
+	});
+	it('should return username', async () => {
+		const tests: [Partial<UserInfo>, string][] = [
+			[
+				{name: "John Doe"},
+				"John Doe",
+			], [
+				{name: "John Doe", email: "some.mail@example.com"},
+				"John Doe",
+			], [
+				{name: "", email: "some.mail@example.com"},
+				"",
+			],
+		];
+		for (const [USER_INFO, RESULT] of tests) {
+			fetchMock.mock('http://demo.url/api/user', {
+				status: 200,
+				body: JSON.stringify(USER_INFO),
+			});
+			const name = await getUserName();
+			expect(name).to.deep.equal(RESULT);
+		}
+	});
+	it('should return default string', async () => {
+		const RESULT = "No name found!";
+		const tests: (Partial<UserInfo>|unknown)[] = [
+			// eslint-disable-next-line no-null/no-null
+			{name: null},
+			// eslint-disable-next-line no-null/no-null
+			null,
+			{email: "some.mail@example.com"},
+			{name: undefined},
+			{},
+		];
+		for (const USER_INFO of tests) {
+			fetchMock.mock('http://demo.url/api/user', {
+				status: 200,
+				body: JSON.stringify(USER_INFO),
+			});
+			const name = await getUserName();
+			expect(name).to.deep.equal(RESULT);
+		}
+	});
+});