gem 'db-query-matchers'

describe 'MyCode' do
  context 'when we expect no queries' do
    it 'does not make database queries' do
      expect { subject.make_no_queries }.to_not make_database_queries
    end
  end
  context 'when we expect queries' do
    it 'makes database queries' do
      expect { subject.make_some_queries }.to make_database_queries
    end
  end
  context 'when we expect exactly 1 query' do
    it 'makes database queries' do
      expect { subject.make_one_query }.to make_database_queries(count: 1)
    end
  end
  context 'when we expect max 3 queries' do
    it 'makes database queries' do
      expect { subject.make_several_queries }.to make_database_queries(count: 0..3)
    end
  end
  context 'when we expect a possible range of queries' do
    it 'makes database queries' do
      expect { subject.make_several_queries }.to make_database_queries(count: 3..5)
    end
  end
  context 'when we only care about manipulative queries (INSERT, UPDATE, DELETE)' do
    it 'makes a destructive database query' do
      expect { subject.make_one_query }.to make_database_queries(manipulative: true)
    end
  end
  context 'when we only care about unscoped queries (SELECT without a WHERE or LIMIT clause))' do
    it 'makes an unscoped database query' do
      expect { subject.make_one_query }.to make_database_queries(unscoped: true)
    end
  end
  context 'when we only care about queries matching a certain pattern' do
    it 'makes a destructive database query' do
      expect { subject.make_special_queries }.to make_database_queries(matching: 'DELETE * FROM')
    end
    it 'makes a destructive database query matched with a regexp' do
      expect { subject.make_special_queries }.to make_database_queries(matching: /DELETE/)
    end
  end
end

DBQueryMatchers.configure do |config|
  config.ignores = [/SHOW TABLES LIKE/]
  config.ignore_cached = true
  config.schemaless = true
  # the payload argument is described here:
  # https://edgeguides.rubyonrails.org/active_support_instrumentation.html#sql-active-record
  config.on_query_counted do |payload|
    # do something arbitrary with the query
  end
  config.log_backtrace = true
  config.backtrace_filter = Proc.new do |backtrace|
    backtrace.select { |line| line.start_with?(Rails.root.to_s) }
  end
end