finch metrics test with idle connections

finch_test.exs

test "get pool status with not reusable connections", %{bypass: bypass, finch_name: finch_name} do
    start_supervised!(
      {Finch,
       name: finch_name,
       pools: %{
         default: [
           protocols: [:http1],
           start_pool_metrics?: true,
           conn_max_idle_time: 1,
           size: 10
         ]
       }}
    )

    shp = shp_from_bypass(bypass)

    parent = self()

    Bypass.expect(bypass, "GET", "/", fn conn ->
      ["number", number] = String.split(conn.query_string, "=")
      send(parent, {:ping_bypass, number})
      Process.sleep(:timer.seconds(1))
      Plug.Conn.send_resp(conn, 200, "OK")
    end)

    refs =
      Enum.map(1..8, fn i ->
        ref =
          Finch.build(:get, endpoint(bypass, "?number=#{i}"))
          |> Finch.async_request(finch_name)

        {ref, i}
      end)

    assert_receive {:ping_bypass, "8"}, 500

    assert {:ok,
            [
              %PoolMetrics{
                pool_index: 1,
                pool_size: 10,
                available_connections: 2,
                in_use_connections: 8
              }
            ]} = Finch.get_pool_status(finch_name, shp)

    Enum.each(refs, fn {req_ref, _number} -> assert_receive({^req_ref, {:status, 200}}, 2000) end)

    wait_connection_checkin()

    assert {:ok,
            [
              %PoolMetrics{
                pool_index: 1,
                pool_size: 10,
                available_connections: 10,
                in_use_connections: 0
              }
            ]} = Finch.get_pool_status(finch_name, shp)
            
    # For now on the connections on the pool will be closed due to idle timeout
    
    refs =
      Enum.map(1..8, fn i ->
        ref =
          Finch.build(:get, endpoint(bypass, "?number=#{i}"))
          |> Finch.async_request(finch_name)

        {ref, i}
      end)

    assert_receive {:ping_bypass, "8"}, 500

    assert {:ok,
            [
              %PoolMetrics{
                pool_index: 1,
                pool_size: 10,
                available_connections: 2,
                in_use_connections: 8
              }
            ]} = Finch.get_pool_status(finch_name, shp)

    Enum.each(refs, fn {req_ref, _number} -> assert_receive({^req_ref, {:status, 200}}, 2000) end)

    wait_connection_checkin()

    assert {:ok,
            [
              %PoolMetrics{
                pool_index: 1,
                pool_size: 10,
                available_connections: 10,
                in_use_connections: 0
              }
            ]} = Finch.get_pool_status(finch_name, shp)
end