Help write the usability scripts for alpha testing of gutenberg

There are 3 new issues on the editor repo that need contribution help, writing the test scripts for alpha testing. These tests are important and a great chance to get involved:

Test one – comparison: https://github.com/WordPress/gutenberg/issues/649
Test two – new content: https://github.com/WordPress/gutenberg/issues/650
Test three – discoverability and feel: https://github.com/WordPress/gutenberg/issues/652