Added GroupTabs test file.

addons/knobs/src/components/__tests__/GroupTabs.js

@@ -0,0 +1,58 @@
+import React from 'react';
+import { shallow } from 'enzyme';
+import GroupTabs from '../GroupTabs';
+
+describe('GroupTabs', () => {
+  test('should render only the selected group with display set other than "none"', () => {
+    const groups = {
+      test1: {
+        render() {
+          return <div id="test1">TEST 1</div>;
+        },
+      },
+      test2: {
+        render() {
+          return <div id="test2">TEST 2</div>;
+        },
+      },
+    };
+
+    const onGroupSelect = () => 'onGroupSelect';
+
+    const wrapper = shallow(
+      <GroupTabs groups={groups} onGroupSelect={onGroupSelect} selectedGroup="test2" />
+    );
+
+    expect(wrapper.find('#test1').parent()).toHaveStyle('display', 'none');
+    expect(wrapper.find('#test2').parent()).not.toHaveStyle('display', 'none');
+  });
+
+  test('should set onGroupSelected as onClick handlers of tabs', () => {
+    const groups = {
+      test1: {
+        render() {
+          return <div>TEST 1</div>;
+        },
+      },
+    };
+    const onGroupSelect = jest.fn();
+    const preventDefault = jest.fn();
+    const wrapper = shallow(
+      <GroupTabs groups={groups} onGroupSelect={onGroupSelect} selectedGroup="test1" />
+    );
+    wrapper.find('button').simulate('click', { preventDefault });
+
+    expect(onGroupSelect).toHaveBeenCalled();
+    expect(preventDefault).toHaveBeenCalled();
+  });
+
+  describe('when no groups are given', () => {
+    test('should render "no groups available"', () => {
+      const groups = {};
+      const onGroupSelect = () => 'onGroupSelect';
+      const wrapper = shallow(<GroupTabs groups={groups} onGroupSelect={onGroupSelect} />);
+
+      expect(wrapper.contains('no groups available')).toBe(true);
+    });
+  });
+});