adding enzyme test

step2-04/README.md

@@ -14,6 +14,8 @@ https://jestjs.io/
 
 # Demo
 
+## jest basics
+
 In this repo, we can start an inner loop development of tests with the command: `npm test`
 
 Take a look at code inside `demo/src`:
@@ -24,10 +26,43 @@ Take a look at code inside `demo/src`:
 
 3. `index.spec.ts` is the test file: note how tests are re-run on save to test file changes as well as source code changes under `src`
 
+## testing React applications
+
+You can also test React Components with `jest` with the help of a partner library called `enzyme`. Take a look at the test below:
+
+```ts
+import { mount } from 'enzyme';
+
+describe('Foo Component Tests', () => {
+  it('allows us to set props', () => {
+    const wrapper = mount(<Foo bar="baz" />);
+    expect(wrapper.props().bar).toBe('baz');
+    wrapper.setProps({ bar: 'foo' });
+    expect(wrapper.props().bar).toBe('foo');
+  });
+});
+```
+
+`mount` does a full mount of the component. You can use the `enzyme` wrapper to simulate clicks, etc:
+
+```ts
+wrapper.find('button').simulate('click');
+```
+
 # Exercise
 
+## Basic Testing
+
 1. Run the tests by running `npm test` at the root of the bootcamp project
 
 2. Look at the `stack.ts` for a sample implementation of a stack
 
 3. Follow the instructions inside the `stack.spec.ts` file to complete the two tests
+
+## Enzyme Testing
+
+1. Open up `exercise/src/TestMe.spec.tsx`
+
+2. Fill in the blank for the missing test using `enzyme` concepts introduced from the demo
+
+3. Run tests with `npm test`