What's causing knex migrate:latest to fail in Shippable?

I'm working on standing up a CI environment on Shippable. I'm at a point where I have a test database and I need to run my migrations against it, but I get an error that makes no sense to me

The build step being executed is this:

(cd www && NODE_ENV=test knex --knexfile ./config/knexplus.js migrate:latest)

The output is this:

Working directory changed to ~/src/github.com/org/api/www/config
Using environment: test
Knex:warning - Pool2 - Error: Pool was destroyed
Knex:Error Pool2 - Error: ER_DBACCESS_DENIED_ERROR: Access denied for user ''@'localhost' to database 'my_test'
Knex:Error Pool2 - Error: ER_DBACCESS_DENIED_ERROR: Access denied for user ''@'localhost' to database 'my_test'
Error: Pool was destroyed

Don't get me wrong, I understand the message, but not why I receive it. Before running the migrations, I have the build dumping the knexplus.js file content:

(cd www && cat ./config/knexplus.js)
  'use strict';

  exports.vagrant = exports.staging = exports.production = {
      client: 'mysql',
      connection: {
          host: '127.0.0.1',
          port: '3306',
          user: 'shippable',
          password: '',
          database: 'mine',
          timezone: 'UTC',
          charset: 'utf8',
          debug: false
      },
      migrations: {
          tableName: '_migrations',
          directory: '../db/migrations'
      },
      seeds: {
          directory: '../db/seeds'
      }
  };

  exports.test = {
      client: 'mysql',
      connection: {
          host: '127.0.0.1',
          port: '3306',
          user: 'shippable',
          password: '',
          database: 'my_test',
          timezone: 'UTC',
          charset: 'utf8',
          debug: false
      },
      migrations: {
          tableName: '_migrations',
          directory: '../db/migrations'
      },
      seeds: {
          directory: '../db/seeds'
      }
  };

What I notice is that the error message seems to indicate that we're grabbing the right configuration since it's referencing the my_test database, but the username and host are wrong.

Any idea what I might be missing here?

Solution

I ended up entering a support ticket and got this response:

The databases in the new default images don't have a "shippable" user, so MySQL notices that someone is trying to connect as a user that doesn't exist and tries to see if you can connect without a username. You can either create a shippable user by adding mysql -e "GRANT ALL ON *.* TO shippable@localhost IDENTIFIED BY ''; FLUSH PRIVILEGES;" to your shippable.yml in the ci section before connecting or connect as the root user.

All of the documentation I was reading at the time had the shippable user. The first step is finding the right documentation, I guess.