basic dropdown tests

src/Dropdown/Dropdown.test.jsx

+/* eslint-disable import/no-extraneous-dependencies */
+import React from 'react';
+import { shallow } from 'enzyme';
+
+import Dropdown from './index';
+
+const props = {
+  title: 'Example',
+  menuItems: [
+    { label: 'Example 1', href: 'http://example1.com' },
+    { label: 'Example 2', href: 'http://example2.com' },
+  ],
+};
+
+describe('<Dropdown />', () => {
+  it('renders correctly', () => {
+    const wrapper = shallow(
+      <Dropdown
+        {...props}
+      />,
+    );
+
+    const menu = wrapper.find('ul');
+    const button = wrapper.find('[type="button"]');
+
+    expect(button.exists()).toEqual(true);
+    expect(button.prop('aria-expanded')).toEqual(false);
+
+    expect(menu.exists()).toEqual(true);
+    expect(menu.find('li')).toHaveLength(2);
+    expect(menu.prop('aria-label')).toEqual(props.title);
+    expect(menu.prop('aria-hidden')).toEqual(true);
+  });
+
+  it('renders correctly', () => {
+    const wrapper = shallow(
+      <Dropdown
+        {...props}
+      />,
+    );
+
+    expect(wrapper.find('[type="button"]').exists()).toEqual(true);
+    expect(wrapper.find('li')).toHaveLength(2);
+    expect(wrapper.find('[aria-expanded=false]').exists()).toEqual(true);
+  });
+
+  it('opens on click', () => {
+    const wrapper = shallow(
+      <Dropdown
+        {...props}
+      />,
+    );
+
+    const button = wrapper.find('[type="button"]');
+
+    button.simulate('click');
+    expect(wrapper.find('[aria-hidden=false]').exists()).toEqual(true);
+  });
+});

src/Dropdown/index.jsx

@@ -45,7 +45,7 @@ class Dropdown extends React.Component {
   }
 
   componentDidUpdate() {
-    if (this.state.open) {
+    if (this.state.open && this.menuItems.length > 0) {
       this.menuItems[this.state.focusIndex].focus();
     } else if (this.toggleElem) {
       this.toggleElem.focus();