1 files changed, 19 insertions, 0 deletions
diff --git a/test/resolv/test_dns.rb b/test/resolv/test_dns.rb
index 1b44f32807..1ac3aea7b8 100644
--- a/test/resolv/test_dns.rb
+++ b/test/resolv/test_dns.rb
@@ -3,6 +3,7 @@ require 'test/unit'
 require 'resolv'
 require 'socket'
 require 'tempfile'
+require 'minitest/mock'
 
 class TestResolvDNS < Test::Unit::TestCase
   def setup
@@ -246,4 +247,22 @@ class TestResolvDNS < Test::Unit::TestCase
     }
     assert_operator(2**14, :<, m.to_s.length)
   end
+
+  def assert_no_fd_leak
+    socket = assert_throw(self) do |tag|
+      Resolv::DNS.stub(:bind_random_port, ->(s, *) {throw(tag, s)}) do
+        yield.getname("8.8.8.8")
+      end
+    end
+
+    assert_predicate(socket, :closed?, "file descriptor leaked")
+  end
+
+  def test_no_fd_leak_connected
+    assert_no_fd_leak {Resolv::DNS.new(nameserver_port: [['127.0.0.1', 53]])}
+  end
+
+  def test_no_fd_leak_unconnected
+    assert_no_fd_leak {Resolv::DNS.new}
+  end
 end