✅ Add tests for #add_response_handler

There weren't any response_handler tests at all, prior to this!

Author: nevans

test/net/imap/test_imap_response_handlers.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "net/imap"
+require "test/unit"
+require_relative "fake_server"
+
+class IMAPResponseHandlersTest < Test::Unit::TestCase
+  include Net::IMAP::FakeServer::TestHelper
+
+  def setup
+    Net::IMAP.config.reset
+    @do_not_reverse_lookup = Socket.do_not_reverse_lookup
+    Socket.do_not_reverse_lookup = true
+    @threads = []
+  end
+
+  def teardown
+    if !@threads.empty?
+      assert_join_threads(@threads)
+    end
+  ensure
+    Socket.do_not_reverse_lookup = @do_not_reverse_lookup
+  end
+
+  test "#add_response_handlers" do
+    responses = []
+    with_fake_server do |server, imap|
+      server.on("NOOP") do |resp|
+        3.times do resp.untagged("#{_1} EXPUNGE") end
+        resp.done_ok
+      end
+
+      assert_equal 0, imap.response_handlers.length
+      imap.add_response_handler do responses << [:block, _1] end
+      assert_equal 1, imap.response_handlers.length
+      imap.add_response_handler(->{ responses << [:proc, _1] })
+      assert_equal 2, imap.response_handlers.length
+
+      imap.noop
+      3.times do |i|
+        assert_pattern do
+          responses[2 * i] => [
+            :block, Net::IMAP::UntaggedResponse[name: "EXPUNGE", data: i]
+          ]
+        end
+        assert_pattern do
+          responses[2 * i + 1] => [
+            :proc,  Net::IMAP::UntaggedResponse[name: "EXPUNGE", data: i]
+          ]
+        end
+      end
+    end
+  end
+
+end