Fixes a issue that happens when the response headers contains only on…

…e 'set-cookie' entry.

src/clj/http/async/client/headers.clj

@@ -64,7 +64,8 @@
   "Creates cookies from headers."
   [headers]
   (if (contains? headers :set-cookie)
-    (for [cookie-string (:set-cookie headers)]
+    (for [cookie-string (let [set-cookie (:set-cookie headers)]
+                          (if (string? set-cookie) (vector set-cookie) set-cookie))]
       (let [name-token (atom true)]
         (into {}
               (for [#^String cookie (.split cookie-string ";")]

test/http/async/client/test.clj

@@ -136,7 +136,7 @@
            constraint (Constraint.)
            mapping (ConstraintMapping.)
            security (ConstraintSecurityHandler.)]
-       
+
        (.addBean srv loginSrv)
        (doto constraint
          (.setName Constraint/__BASIC_AUTH)
@@ -481,6 +481,16 @@
       (is (thrown-with-msg? RuntimeException #"Too many connections 1" (GET client url)))
       (is (not (failed? (await r1)))))))
 
+
+(deftest single-set-cookie
+  (let [resp (GET *client* "http://localhost:8123/cookie")
+        cookie (first (cookies resp))
+        header (headers resp)]
+    (is (string? (:set-cookie header)))
+    (is (= (:name cookie) "foo"))
+    (is (= (:value cookie) "bar"))))
+
+
 (deftest await-string
   (let [resp (GET *client* "http://localhost:8123/stream")
         body (string (await resp))]