Instrumenting the spec run to catch test data leakage at the source. Use like this: bundle exec rspec --seed _(seed number here)_ file1 file2 file3 ...

spec_helper.rb

...

def check_for_pollution
  tables_with_records = []
  all_tables = ActiveRecord::Base.connection.tables
  all_tables.each do |table_name|
    has_records = (ActiveRecord::Base.connection.select_value("select exists (select 1 from #{table_name} limit 1)") > 0)
    tables_with_records << table_name if has_records
  end
  expected_tables_with_records = ['schema_migrations']
  unexpected_tables_with_records = tables_with_records - expected_tables_with_records
  raise "Tables with post-spec pollution: #{unexpected_tables_with_records.inspect}" unless unexpected_tables_with_records.empty?
  unexpected_tables_with_records.should == []
end

require 'spork'

Spork.prefork do
  ...

  RSpec.configure do |config|
    # config.formatter = EarlyInfoFormatter # :documentation, :progress, :html, :textmate, AnxiousFormatter, EarlyInfoFormatter
    config.formatter = :documentation
    ...

    config.before :each do
      ...
      check_for_pollution
    end

  end
end

...