Expand create_user test to include all possible parameters.
Return 404 status for invalid user ids.
Add tests for Users Controller get_item method error responses.
Add test for error response for current user endpoint.
Add unit tests for error conditions of create user endpoint.
Add unit test for error response of user collection endpoint.
Remove error condition for calls to prepare_item_for_database method.

WP_JSON_Users_Controller->prepare_item_for_database never returns a WP_Error.
Add unit tests for error conditions for update users endpoint.
Fix invalid id tests for multisite.
Add unit tests for error responses for delete user endpoint.
Merge pull request #744 from WP-API/users-tests

Full Test Coverage for Users Controller