Merge pull request react-dates#1912 from airbnb/update-tests-for-keyboard-shortcuts-fix

Adding test for react-dates#1911

Author: kevinthepan

test/components/DayPickerKeyboardShortcuts_spec.jsx

@@ -145,6 +145,14 @@ describe('DayPickerKeyboardShortcuts', () => {
           const wrapper = shallow(<DayPickerKeyboardShortcuts {...props} />).dive();
           expect(wrapper.children().find(Button)).to.have.lengthOf(1);
         });
+
+        it('renders the default button if renderKeyboardShortcutsButton is not provided', () => {
+          const wrapper = shallow(<DayPickerKeyboardShortcuts />).dive();
+          expect(wrapper.children().find('button')).to.have.lengthOf(1);
+          expect(wrapper.children().find('button').prop('aria-label')).to.eql(
+            DayPickerKeyboardShortcutsPhrases.showKeyboardShortcutsPanel,
+          );
+        });
       });
 
       describe('renderKeyboardShortcutsPanel', () => {