use enzyme and update tests

package.json

@@ -3,14 +3,17 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
+    "enzyme": "^3.3.0",
+    "enzyme-adapter-react-16": "^1.1.1",
     "react": "^16.2.0",
     "react-dom": "^16.2.0",
-    "react-scripts": "1.1.1"
+    "react-scripts": "1.1.1",
+    "react-test-renderer": "^16.3.0"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
     "test": "react-scripts test --env=jsdom",
     "eject": "react-scripts eject"
   }
-}
+}

src/App.test.js

@@ -1,12 +1,22 @@
 import React from 'react';
-import ReactDOM from 'react-dom';
+import renderer from 'react-test-renderer';
+import { mount, shallow } from 'enzyme';
 import App from './App';
-import setupBrowserMocks from './utils/browserMocks';
 
-setupBrowserMocks();
+describe('App', () => {
+  it('renders correctly', () => {
+    const wrapper = shallow(<App />);
+    expect(wrapper.find('WeightCheckboxes')).toHaveLength(2);
+    expect(wrapper.find('WeightResults')).toHaveLength(1);
+  });
 
-it('renders without crashing', () => {
-  const div = document.createElement('div');
-  ReactDOM.render(<App />, div);
-  ReactDOM.unmountComponentAtNode(div);
+  it('changing weight works correctly', () => {
+    const expectedResults = 'Add these weights to each side of the barbell to get 200 lbs:';
+    const wrapper = mount(<App />);
+    wrapper.find('.input-weight').simulate('change', {
+      target: { value: 200 },
+    });
+    wrapper.find('form').simulate('submit');
+    expect(wrapper.find('.weight-results p').text()).toBe(expectedResults);
+  });
 });

src/utils/browserMocks.js → src/setupTests.js

@@ -1,6 +1,8 @@
-var localStorageMock = (function() {
-  var store = {};
+import { configure } from 'enzyme';
+import Adapter from 'enzyme-adapter-react-16';
 
+const localStorageMock = (function() {
+  const store = {};
   return {
     getItem: function(key) {
       return store[key] || null;
@@ -12,13 +14,8 @@ var localStorageMock = (function() {
       store = {};
     }
   };
-
 })();
 
-var setupBrowserMocks = function() {
-  Object.defineProperty(window, 'localStorage', {
-   value: localStorageMock
-  });
-}
+global.localStorage = localStorageMock;
 
-export default setupBrowserMocks;
+configure({ adapter: new Adapter() });