blockscout/test/mix/tasks/scrape_test.exs

defmodule Scrape.Test do
  use Explorer.DataCase
  alias Explorer.Block
  alias Explorer.Repo

  test "it downloads a new block" do
    use_cassette "scrape" do
      Mix.Tasks.Scrape.run([])

      last_block = Block
        |> order_by(desc: :inserted_at)
        |> limit(1)
        |> Repo.all
        |> List.first

      assert(last_block.number)
    end
  end
end