Add tests for layout

cypress/integration/layout.spec.js

+/**
+ * Copyright (C) 2019  The Software Heritage developers
+ * See the AUTHORS file at the top-level directory of this distribution
+ * License: GNU Affero General Public License version 3, or any later version
+ * See top-level LICENSE file for more information
+ */
+
+const url = '/';
+
+describe('Test top-bar', function() {
+  it('should should contain all navigation links', function() {
+    cy.visit(url);
+    cy.get('.swh-top-bar > ul > li > a')
+      .should('have.length', 5)
+      .and('be.visible')
+      .and('have.attr', 'href');
+  });
+
+  it('should show donate button on lg screen', function() {
+    cy.visit(url);
+    cy.get('.swh-donate-link')
+      .should('be.visible');
+  });
+
+  it('should hide donate button on sm screen', function() {
+    cy.viewport(600, 800);
+    cy.visit(url);
+    cy.get('.swh-donate-link')
+      .should('not.be.visible');
+  });
+});
+
+describe('Test footer', function() {
+  beforeEach(function() {
+    cy.visit(url);
+  });
+
+  it('should be visible', function() {
+    cy.get('footer')
+      .should('be.visible');
+  });
+
+  it('should have correct copyright years', function() {
+    const currentYear = new Date().getFullYear();
+    const copyrightText = '(C) 2015–' + currentYear.toString();
+    cy.get('footer')
+      .should('contain', copyrightText);
+  });
+});