Jest 14 adds snapshot testing: https://facebook.github.io/jest/blog/2016/07/27/jest-14.html. One of the advantages is that it allows snapshots to be automatically updated by running jest -u.

Currently we manually load the expected result and compare with toEqual: https://github.com/facebook/jscodeshift/blob/master/src/testUtils.js#L68. I think this could be replaced with snapshot testing, avoiding the need for us to manually load the file containing the expected result.