Testing header presensce

lib/rack/accept/header.rb

@@ -98,6 +98,12 @@ def accept?(value)
         qvalue(value) != 0
       end
 
+      # Determines if the given header had a +value+ set, if not the header can
+      # be regarded as not having been present in the HTTP connection.
+      def present?
+        !values.empty?
+      end
+
       # Returns a copy of the given +values+ array, sorted by quality factor
       # (qvalue). Each element of the returned array is itself an array
       # containing two objects: 1) the value's qvalue and 2) the original

test/language_test.rb

@@ -13,6 +13,13 @@ def test_qvalue
     assert_equal(0, l.qvalue('da'))
   end
 
+  def test_present?
+    header = 'da, en-gb;q=0.8, en;q=0.7'
+    assert_true(L.new(header).present?)
+    header = ''
+    assert_false(L.new(header).present?)
+  end
+
   def test_matches
     l = L.new('da, *, en')
     assert_equal(%w{*}, l.matches(''))