add test for calendar dropdown

package.json

@@ -58,6 +58,7 @@
     "node-sass": "^3.10.1",
     "react": "^15.3.2",
     "react-addons-test-utils": "^15.3.2",
+    "react-day-picker": "^3.1.1",
     "react-dom": "^15.3.2",
     "stylelint": "^7.4.2",
     "stylelint-scss": "^1.3.4",
@@ -76,6 +77,7 @@
     "piping": "^1.0.0-rc.4",
     "postcss-loader": "^1.1.1",
     "sass-loader": "^4.0.2",
+    "sinon": "^1.17.7",
     "style-loader": "^0.13.1",
     "svg-loader": "0.0.2"
   },

src/components/calendar/calendarDropdown.jsx

@@ -2,7 +2,7 @@ import React from 'react';
 import DayPicker from 'react-day-picker';
 import 'react-day-picker/lib/style.css';
 
-export const CalendarDropdown = () => (
+const CalendarDropdown = () => (
   <div className="ui dropdown menu">
     <div className="content">
       <DayPicker

src/components/calendar/calendarDropdown.test.jsx

@@ -0,0 +1,27 @@
+import React from 'react';
+import { expect } from 'chai';
+import { shallow } from 'enzyme';
+import DayPicker from 'react-day-picker';
+import CalendarDropdown from './calendarDropdown';
+
+describe('<CalendarDropdown />', () => {
+  let wrapper;
+  beforeEach(() => {
+    wrapper = shallow(<CalendarDropdown />);
+  });
+  it('should render only one dropdown', () => {
+    expect(wrapper.find('.ui .dropdown .menu')).to.have.length(1);
+  });
+
+  it('should render the `show today` button', () => {
+    expect(wrapper.find('.ui .basic .button').text()).to.equal('Show Today');
+  });
+
+  it('should render the main contenet', () => {
+    expect(wrapper.find('.content')).to.have.length(1);
+  });
+
+  it('should render the day picker component with an initialMonth', () => {
+    expect(wrapper.contains(<DayPicker initialMonth={new Date(2017, 0)} />)).to.equal(true);
+  });
+});