refactor(UrlHelpers): [#715] created safelyAppendUrlParameter method

src/helpers/url.ts

+export function safelyAppendUrlParameter (url: string, parameterKey: string, parameterValue: string): string {
+  const separator = url.includes('?') ? '&' : '?';
+  return `${url}${separator}${parameterKey}=${parameterValue}`;
+}

test/application/helpers/url.test.ts

+import { safelyAppendUrlParameter } from '../../../src/helpers/url';
+
+describe('safelyAppendUrlParameter method', function () {
+  let fixtureUrl: string;
+  const fixtureParameterKey = 'parameterKey';
+  const fixtureParameterValue = 'parameterValue';
+
+  describe('given the url already has parameter', function () {
+    it('should return the url with the parameter correctly appended', function () {
+      fixtureUrl = 'https://www.domain.tld/path/to/page?key=value';
+      const assertionURL = `${fixtureUrl}&${fixtureParameterKey}=${fixtureParameterValue}`;
+      expect(safelyAppendUrlParameter(fixtureUrl, fixtureParameterKey, fixtureParameterValue))
+        .toEqual(assertionURL);
+    });
+  });
+
+  describe('given the url does not already have parameter', function () {
+    it('should return the url with the parameter correctly appended', function () {
+      fixtureUrl = 'https://www.domain.tld/path/to/page';
+      const assertionURL = `${fixtureUrl}?${fixtureParameterKey}=${fixtureParameterValue}`;
+      expect(safelyAppendUrlParameter(fixtureUrl, fixtureParameterKey, fixtureParameterValue))
+        .toEqual(assertionURL);
+    });
+  });
+});