Make HTTP::Cookie Comparable.

lib/http/cookie.rb

@@ -300,6 +300,17 @@ class HTTP::Cookie
     "#{@name}=#{@value}"
   end
 
+  # Compares the cookie with another.  When there are many cookies with
+  # the same name for a URL, the value of the smallest must be used.
+  def <=>(other)
+    # RFC 6265 5.4
+    # Precedence: 1. longer path  2. older creation
+    (@name <=> other.name).nonzero? ||
+      (other.path.length <=> @path.length).nonzero? ||
+      @created_at <=> other.created_at
+  end
+  include Comparable
+
   # YAML serialization helper for Syck.
   def to_yaml_properties
     PERSISTENT_PROPERTIES.map { |name| "@#{name}" }

lib/http/cookie_jar.rb

@@ -51,11 +51,7 @@ class HTTP::CookieJar
 
     select { |cookie|
       !cookie.expired? && cookie.valid_for_uri?(url) && (cookie.accessed_at = now)
-    }.sort_by { |cookie|
-      # RFC 6265 5.4
-      # Precedence: 1. longer path  2. older creation
-      [-cookie.path.length, cookie.created_at]
-    }
+    }.sort
   end
 
   def empty?(url)

test/test_http_cookie_jar.rb

@@ -123,6 +123,27 @@ class TestHTTPCookieJar < Test::Unit::TestCase
     assert_equal(0, @jar.cookies(URI('http://google.com/')).length)
   end
 
+  def test_add_multiple_cookies_with_the_same_name
+    now = Time.now
+
+    cookies = [
+      { :value => 'a', :path => '/', },
+      { :value => 'b', :path => '/abc/def/', :created_at => now - 1 },
+      { :value => 'c', :path => '/abc/def/', :domain => 'www.rubyforge.org', :created_at => now },
+      { :value => 'd', :path => '/abc/' },
+    ].map { |attrs|
+      HTTP::Cookie.new(cookie_values(attrs))
+    }
+
+    url = URI 'http://www.rubyforge.org/abc/def/ghi'
+
+    cookies.permutation(cookies.size) { |shuffled|
+      @jar.clear
+      shuffled.each { |cookie| @jar.add(url, cookie) }
+      assert_equal %w[b c d a], @jar.cookies(url).map { |cookie| cookie.value }
+    }
+  end
+
   def test_add_rejects_cookies_that_do_not_contain_an_embedded_dot
     url = URI 'http://rubyforge.org/'