snapshot_repository_test.exs

defmodule MyApp.SnapshotRepositoryTest do
  use ExUnit.Case, async: true
  doctest MyApp.SnapshotRepository
  alias MyApp.SnapshotRepository.SnapshotOptions

  test "queries S3 with a prefix and returns the matched keys" do
    options = %SnapshotOptions{ campaign_id: "prod.0.1", backend: "SomeBackend", cycle_type: "week" }
    prefix  = SnapshotOptions.to_key_prefix(options)
    key_1   = "#{prefix}0/2013-03-19T15:04:50Z/mtoken.json.gz"
    key_2   = "#{prefix}1/2013-03-19T15:04:50Z/mtoken.json.gz"

    defmodule FakeS3 do
      def list_objects!(_bucket_name, prefix: prefix) do
        # would be nice to not have to define these keys a second time,
        # but we can't access `key_1` and `key_2` from here :(.
        key_1 = "#{prefix}0/2013-03-19T15:04:50Z/mtoken.json.gz"
        key_2 = "#{prefix}1/2013-03-19T15:04:50Z/mtoken.json.gz"
        %HTTPoison.Response{body: %{contents: [ %{ key: key_1 }, %{ key: key_2 } ] }, status_code: 200}
      end
    end

    keys = MyApp.SnapshotRepository.find_snapshot_keys(options, FakeS3)
    assert keys == [key_1, key_2]
  end

  test "dedups keys for the same cycle type, selecting the one with the later timestamp" do
    options = %SnapshotOptions{ campaign_id: "prod.0.1", backend: "SomeBackend", cycle_type: "week" }
    prefix  = SnapshotOptions.to_key_prefix(options)
    key_1   = "#{prefix}0/2013-03-19T15:04:50Z/mtoken.json.gz"
    key_2   = "#{prefix}0/2013-03-21T15:04:50Z/mtoken.json.gz" # the latest one
    key_3   = "#{prefix}0/2013-03-20T15:04:50Z/mtoken.json.gz"

    # To avoid Elixir module redef warnings, we need to use a different module name here...
    defmodule FakeS3_2 do
      def list_objects!(_bucket_name, prefix: prefix) do
        key_1 = "#{prefix}0/2013-03-19T15:04:50Z/mtoken.json.gz"
        key_2 = "#{prefix}0/2013-03-21T15:04:50Z/mtoken.json.gz" # the latest one
        key_3 = "#{prefix}0/2013-03-20T15:04:50Z/mtoken.json.gz"
        %HTTPoison.Response{body: %{contents: [ %{ key: key_1 }, %{ key: key_2 }, %{ key: key_3 } ] }, status_code: 200}
      end
    end

    keys = MyApp.SnapshotRepository.find_snapshot_keys(options, FakeS3_2)
    assert keys == [key_2]
  end

  test "fails if S3 responds with a non-200 status" do
    options = %SnapshotOptions{ campaign_id: "prod.0.1", backend: "SomeBackend", cycle_type: "week" }
    prefix  = SnapshotOptions.to_key_prefix(options)

    defmodule FakeS3_3 do
      def list_objects!(_bucket_name, prefix: prefix) do
        key_1 = "#{prefix}0/2013-03-19T15:04:50Z/mtoken.json.gz"
        %HTTPoison.Response{body: %{contents: [ %{ key: key_1 } ] }, status_code: 404}
      end
    end

    assert_raise MyApp.SnapshotRepository.UnsuccessfulS3ResponseError, ~r/expected a 200 response.*got a 404/i, fn ->
      MyApp.SnapshotRepository.find_snapshot_keys(options, FakeS3_3)
    end
  end
end