module ThreadSafe describe Hash do let!(:hsh) { described_class.new } it 'concurrency' do (1..THREADS).map do |i| Thread.new do 1000.times do |j| hsh[i * 1000 + j] = i hsh[i * 1000 + j] hsh.delete(i * 1000 + j) end end end.map(&:join) end end end