diff --git a/test/net/smtp/test_response.rb b/test/net/smtp/test_response.rb
new file mode 100644
index 0000000000..696a72157f
--- /dev/null
+++ b/test/net/smtp/test_response.rb
@@ -0,0 +1,37 @@
+require 'net/smtp'
+require 'minitest/autorun'
+
+module Net
+  class SMTP
+    class TestResponse < MiniTest::Unit::TestCase
+      def test_capabilities
+        res = Response.parse("250-ubuntu-desktop\n250-PIPELINING\n250-SIZE 10240000\n250-VRFY\n250-ETRN\n250-STARTTLS\n250-ENHANCEDSTATUSCODES\n250 DSN\n")
+
+        capabilities = res.capabilities
+        %w{ PIPELINING SIZE VRFY STARTTLS ENHANCEDSTATUSCODES DSN}.each do |str|
+          assert capabilities.key?(str), str
+        end
+      end
+
+      def test_capabilities_default
+        res = Response.parse("250-ubuntu-desktop\n250-PIPELINING\n250 DSN\n")
+        assert_equal [], res.capabilities['PIPELINING']
+      end
+
+      def test_capabilities_value
+        res = Response.parse("250-ubuntu-desktop\n250-SIZE 1234\n250 DSN\n")
+        assert_equal ['1234'], res.capabilities['SIZE']
+      end
+
+      def test_capabilities_multi
+        res = Response.parse("250-ubuntu-desktop\n250-SIZE 1 2 3\n250 DSN\n")
+        assert_equal %w{1 2 3}, res.capabilities['SIZE']
+      end
+
+      def test_bad_string
+        res = Response.parse("badstring")
+        assert_equal({}, res.capabilities)
+      end
+    end
+  end
+end