How to get full test coverage with Jest and ReactJS, currently at 90.48% statements, 58.06% branch

Question

With the simplest ReactJS component Jest is not reporting full test coverage. How to get statements and branch to show 100%.

Currently Jest shows 90.48% statements, 58.06% branch. Run with jest --coverage.

MyThing.js

import React from 'react';

export default class MyThing extends React.Component {
  render() {
    return (
      <div>
        Stuff
      </div>
    );
  }
}

MyThing-test.js

// __tests__/MyThing-test.js

jest.unmock('../app/views/static/MyThing');

import React from 'react';
import ReactDOM from 'react-dom';
import TestUtils from 'react-addons-test-utils';

import MyThing from '../app/views/static/MyThing';


describe('MyThing', () => {

    const instance = TestUtils.renderIntoDocument(
        <MyThing />
    );          

  it('gets rendered', () => {    
    expect( TestUtils.isCompositeComponent(instance) ).toBeTruthy();        
  });


  it('is not DOM component', () => {   
   // checks if is a standard DOM element, i.e. <div>
    expect( TestUtils.isDOMComponent(instance) ).not.toEqual(true);    
  });

  it('isElementOfType is React element', () => {  
    expect( TestUtils.isElementOfType(<MyThing />, MyThing) ).toEqual(true);
  });

  it('render()', () => {    
    const retVal = instance.render();

    expect( retVal.type ).toEqual("div");       
  });

});

Answer 1

This is most likely due to the transpiled code from babel. See issue #817 where this issue was worked on and just recently resolved.

This should be fixed with the upgrade to jest@15.

Though some people mentioned the need to add sourcemaps to their .babelrc such as:

{
  "env": {
    "test": {
      "sourceMaps": "both"
    }
  }
}

and update their jest to explicitly with "coverageCollector": "jest-babel-istanbul"