add button test

src/tests/common/Button.test.js

@@ -0,0 +1,33 @@
+import React from 'react';
+import { shallow } from 'enzyme';
+import Button from '../../common/Button';
+
+describe('<Button />', () => {
+  const submitHandler = jest.fn();
+  const props = {
+    name: 'stripe-button',
+    value: 'Update Card Details',
+    className: 'btn',
+    onClick: submitHandler,
+    disabled: 'false',
+  };
+
+  const wrapper = shallow(<Button {...props} />);
+
+  it('should render without crashing', () => {
+    expect(wrapper.length).toBe(1);
+  });
+
+  it('should display the value', () => {
+    expect(wrapper.find('.btn').text()).toBe('Update Card Details');
+  });
+
+  it('should have type attribute default value as button', () => {
+    expect(wrapper.props()['type']).toBe('button');
+  });
+
+  it('should call onclick event handler when clicked', () => {
+    wrapper.simulate('click')
+    expect(submitHandler).toBeCalledTimes(1);
+  });
+});