Automatically maintain test database schema

* Move check from generated helper to test_help.rb, so that all
  applications can benefit
* Rather than just raising when the test schema has pending migrations,
  try to load in the schema and only raise if there are pending
  migrations afterwards
* Opt out of the check by setting
  config.active_record.maintain_test_schema = false
* Deprecate db:test:* tasks. The test helper is now fully responsible
  for maintaining the test schema, so we don't need rake tasks for this.
  This is also a speed improvement since we're no longer reloading the
  test database on every call to "rake test".

1 files changed, 2 insertions, 0 deletions

diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index c30b806907..272850d4c5 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -290,6 +290,8 @@ All these configuration options are delegated to the `I18n` library.
 
 * `config.active_record.attribute_types_cached_by_default` sets the attribute types that `ActiveRecord::AttributeMethods` will cache by default on reads. The default is `[:datetime, :timestamp, :time, :date]`.
 
+* `config.active_record.maintain_test_schema` is a boolean value which controls whether Active Record should try to keep your test database schema up-to-date with `db/schema.rb` (or `db/structure.sql`) when you run your tests. The default is true.
+
 The MySQL adapter adds one additional configuration option:
 
 * `ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans` controls whether Active Record will consider all `tinyint(1)` columns in a MySQL database to be booleans and is true by default.