Truncate Almost All Tables

The database_cleaner gem is a handy way to make sure you have a consistent database context for each test example or suite. One database_cleaner strategy that can be used is the truncation strategy. This truncates the data from all the tables by default. This is not ideal for fixed tables that contain domain-specific data because you end up having to do way more test setup than should be necessary. Fortunately, specific tables can be excepted by the truncation strategy using the except option.

For instance, if we have a standard set of roles for users of our application, we can except that table from truncation with a line like the following in our rails_helper.rb file:

DatabaseCleaner.strategy = :truncation, {:except => %w[roles]}