How to purge rows from tables to s3 from a Elixir application using Ports - audit_log_purge_test.exs

audit_log_purge_test.exs

defmodule Mix.Tasks.AuditLogPurgeTest do
  use RkOneApi.DataCase

  import Ecto.Query
  import Ecto.Changeset

  alias MyApp.AuditLog
  alias Mix.Tasks.AuditLogPurge

  defp build_fake_backup_cmd(_, _, _), do: "cat"

  defp create_records(_) do
    do_create_records(%{
      count: 2,
      logged_at: ~N[2019-01-01 14:59:00]
    })

    do_create_records(%{
      count: 2,
      logged_at: ~N[2019-02-01 14:59:00]
    })

    :ok
  end

  defp do_create_records(%{count: count, logged_at: logged_at}) do
    for n <- count..0 do
      AuditLog
      |> change(
        ...
        logged_at: NaiveDateTime.add(logged_at, n)
      )
      |> Repo.insert()
    end
  end

  defp audit_logs_records_to_be_purged do
    from(i in AuditLog)
    |> where(
      [i],
      fragment("date_part('year', ?)", i.logged_at) == 2019
    )
    |> where(
      [i],
      fragment("date_part('month', ?)", i.logged_at) == 1
    )
  end

  defp audit_logs_records_to_be_maintained do
    from(i in AuditLog)
    |> where(
      [i],
      fragment("date_part('year', ?)", i.logged_at) == 2019
    )
    |> where(
      [i],
      fragment("date_part('month', ?)", i.logged_at) == 1
    )
  end

  describe("run/1") do
    setup do
      # Get Mix output sent to the current
      # process to avoid polluting tests.
      Mix.shell(Mix.Shell.Process)

      on_exit(fn ->
        Mix.shell(Mix.Shell.IO)
      end)
    end

    setup [:create_records]

    test "calls the command only with the selected chunk" do
      AuditLogPurge.run(
        ["--year", "2019", "--month", "01"],
        &build_fake_backup_cmd/3
      )

      assert_received {
        :mix_shell,
        :info,
        ["Audit Logs purged successfully!"]
      }

      for record <-
            audit_logs_records_to_be_purged()
            |> Repo.all() do
        encoded_record =
          record
          |> Jason.encode!(pretty: true)
          |> Kernel.<>("\n")

        assert_received {_, {:data, ^encoded_record}}
      end

      for record <-
            audit_logs_records_to_be_maintained()
            |> Repo.all() do
        encoded_record =
          record
          |> Jason.encode!(pretty: true)
          |> Kernel.<>("\n")

        refute_received {_, {:data, ^encoded_record}}
      end

      refute audit_logs_records_to_be_purged() |> Repo.exists?()
      assert audit_logs_records_to_be_maintained() |> Repo.exists?()
    end

    test "raises a message when required params are not present" do
      message = """
      Lacking required year and month arguments.
      Type `mix help audit_log_purge` to know more details.
      """

      assert_raise Mix.Error, message, fn ->
        AuditLogPurge.run([], &build_fake_backup_cmd/3)
      end
    end
  end
end