Write tests for functions that require API access

[benlk]

Most of these functions have stubbed tests, and are all related to pushing and pulling.

The problems with these tests are:

• TravisCI.org needs API credentials that it can use. These can be stored as environment variables in a number of ways, but we'll need to provide a way for the plugin to copy the environment variables for the API creds into the database as a part of the test bootstrapping.
• The Travis server running the tests needs to have its IP address whitelisted. We might be able to do this by whitelisting a range of IP addresses in the ACL so that we can write tests that communicate with the API.