title: jest + graphql integration tests displaying errors
body: <p>I am writing integration tests against my <code>db</code> and <code>graphql</code> server.<br>
  <code>jest</code> is my test runner and assertions library.</p>
  
  <p>For each test, I validate that I don't have any errors:</p>
  
  <pre><code>const actual = await graphql(schema, query);
  expect(actual.errors).toBeUndefined();
  </code></pre>
  
  <p>When my tests are failing (something goes wrong along the way),<br>
  the <code>actual.errors</code> is not <code>undefined</code> and I expect <code>jest</code> to display the errors,<br>
  but this is what I get:</p>
  
  <pre><code>Expected value to be undefined, instead received
    [[GraphQLError: Invalid value [object Object]]]
  </code></pre>
  
  <p>This error message is useless if I can't see what is the "invalid value".<br>
  How can I configure <code>jest</code> so that it will print the error object?</p>