login.test.js

import React from 'react';
import { shallow } from 'react-test-renderer/shallow';
import { Login } from '../';

// it('should render Login without error', () => {
//   expect(Login).toMatchSnapshot();
// });

it('renders without crashing', () => {
  shallow(<Login />);
});

Package.json

{
  "name": "bamms_tcr",
  "version": "0.1.0",
  "private": true,
  "devDependencies": {
    "enzyme": "^2.8.0",
    "eslint-plugin-react": "^7.1.0",
    "jest-expo": "~18.0.0",
    "jest-serializer-enzyme": "^1.0.0",
    "react-native-scripts": "0.0.50",
    "react-test-renderer": "^15.6.1"
  },
  "main": "./node_modules/react-native-scripts/build/bin/crna-entry.js",
  "scripts": {
    "start": "react-native-scripts start",
    "eject": "react-native-scripts eject",
    "android": "react-native-scripts android",
    "ios": "react-native-scripts ios",
    "test": "node node_modules/jest/bin/jest.js --watch"
  },
  "jest": {
    "preset": "jest-expo"
  },
  "dependencies": {
    "axios": "^0.16.2",
    "eslint-config-rallycoding": "^3.2.0",
    "expo": "^18.0.3",
    "jest": "^20.0.4",
    "jest-cli": "^20.0.4",
    "prop-types": "^15.5.10",
    "react": "16.0.0-alpha.12",
    "react-native": "^0.45.1",
    "react-native-elements": "^0.14.0",
    "react-native-vector-icons": "^4.2.0",
    "react-navigation": "^1.0.0-beta.11",
    "react-redux": "^5.0.5",
    "redux": "^3.7.2",
    "redux-logger": "^3.0.6",
    "redux-saga": "^0.15.4",
    "redux-thunk": "^2.2.0"
  }
}