Added tests for header-seq, fixed nil header bug

@@ -7,8 +7,8 @@
   "Returns seq of values for the specified header. Multiple values can be
   encoded in one header key using a comma as a separator."
   [request key]
-  (-> (get-in request [:headers (name key)])
-      (str/split #"\s*,\s*")))
+  (if-let [value (get-in request [:headers (name key)])]
+    (str/split value #"\s*,\s*")))
 
 (defn- parse-attr-map [attrs]
   (->> (map #(str/split % #"=") attrs)

@@ -0,0 +1,17 @@
+(ns ring.util.test.request
+  (:use clojure.test
+        ring.util.request))
+
+(deftest test-header-seq
+  (are [r k hs] (= (header-seq r k) hs)
+    {:headers {"accept" "text/html, text/xml"}}
+    "accept"
+    ["text/html" "text/xml"]
+
+    {:headers {"content-type" "text/html"}}
+    "content-type"
+    ["text/html"]
+
+    {:headers {}}
+    "x-foo"
+    nil))