require "test_helper"

class Mailings::SmtpGateTest < ActiveSupport::TestCase
  setup do
    Mailings::SmtpGate.min_gap = 0
    Mailings::SmtpGate.backoff_base = 0
    Mailings::SmtpGate.max_attempts = 4
    Mailings::SmtpGate.reset!
  end

  teardown do
    Mailings::SmtpGate.min_gap = 0
    Mailings::SmtpGate.backoff_base = 0
    Mailings::SmtpGate.max_attempts = 4
    Mailings::SmtpGate.reset!
  end

  test "retries EOFError then succeeds" do
    hits = 0
    result = Mailings::SmtpGate.deliver do
      hits += 1
      raise EOFError, "end of file reached" if hits < 3

      :sent
    end

    assert_equal :sent, result
    assert_equal 3, hits
  end

  test "gives up after max attempts" do
    hits = 0
    error = assert_raises(EOFError) do
      Mailings::SmtpGate.deliver do
        hits += 1
        raise EOFError, "end of file reached"
      end
    end

    assert_equal "end of file reached", error.message
    assert_equal Mailings::SmtpGate.max_attempts, hits
  end

  test "does not retry permanent SMTP errors" do
    hits = 0
    assert_raises(Net::SMTPAuthenticationError) do
      Mailings::SmtpGate.deliver do
        hits += 1
        raise Net::SMTPAuthenticationError, "535 authentication failed"
      end
    end
    assert_equal 1, hits
  end

  test "serializes concurrent deliveries" do
    order = Queue.new
    threads = 2.times.map do |i|
      Thread.new do
        Mailings::SmtpGate.deliver do
          order << i
          sleep 0.05
        end
      end
    end
    threads.each(&:join)

    assert_equal 2, order.size
  end
end