add spec

spec/dlx_spec.cr

@@ -0,0 +1,32 @@
+require "./spec_helper"
+require "./../src/lavinmq/queue"
+
+describe "Dead lettering" do
+  q_name = "ttl"
+  q_name_delayed = "ttl_delayed"
+  q_name_delayed_2 = "ttl_delayed_2"
+
+  # Verifies bugfix for Sub-table memory corruption in amq-protocol.cr
+  # https://github.com/cloudamqp/amq-protocol.cr/pull/14
+  it "should be able to read messages that has been dead lettered multiple times" do
+    with_channel do |ch|
+      q_delayed_2 = ch.queue(q_name_delayed_2, args: AMQP::Client::Arguments.new(
+        {"x-message-ttl" => 1, "x-dead-letter-exchange" => "", "x-dead-letter-routing-key" => q_name_delayed}
+      ))
+      q_delayed = ch.queue(q_name_delayed, args: AMQP::Client::Arguments.new(
+        {"x-message-ttl" => 1, "x-dead-letter-exchange" => "", "x-dead-letter-routing-key" => q_name}
+      ))
+      q = ch.queue(q_name)
+
+      x = ch.default_exchange
+      x.publish_confirm("ttl", q_delayed_2.name)
+      msg = wait_for { q.get }
+
+      x_death = msg.properties.headers.not_nil!["x-death"].as(Array(AMQ::Protocol::Field))
+      x_death.inspect
+      x_death.size.should eq 2
+      x_death[0].as(AMQ::Protocol::Table)["queue"].should eq q_delayed.name
+      x_death[1].as(AMQ::Protocol::Table)["queue"].should eq q_delayed_2.name
+    end
+  end
+end