Adds tests for the KeyUp event on header

Author: Michael-Hanley

packages/react-bootstrap-table2/test/header-cell.test.js

@@ -393,12 +393,26 @@ describe('HeaderCell', () => {
     it('should have onClick event on header cell', () => {
       expect(wrapper.find('th').prop('onClick')).toBeDefined();
     });
+    
+    it('should have onKeyUp event on header cell', () => {
+      expect(wrapper.find('th').prop('onKeyUp')).toBeDefined();
+    });
 
     it('should trigger onSort callback when click on header cell', () => {
       wrapper.find('th').simulate('click');
       expect(onSortCallBack.callCount).toBe(1);
     });
 
+    it('should trigger onSort callback when keyup Enter on header cell', () => {
+      wrapper.find('th').simulate('keyup', {key: 'Enter'});
+      expect(onSortCallBack.callCount).toBe(1);
+    });
+
+    it('should not trigger onSort callback when keyup key is not Enter on header cell', () => {
+      wrapper.find('th').simulate('keyup', {key: 'test-key'});
+      expect(onSortCallBack.callCount).toBe(0);
+    });
+
     describe('and sorting prop is false', () => {
       it('header should render SortSymbol as default', () => {
         expect(wrapper.find(SortSymbol).length).toBe(1);