Add server-side tests for the Ring handler

The test suite only covered eval round-trips through a real Jetty server
via drawbridge.client-test. This adds direct Ring-level tests for the
handler returned by ring-handler, covering method rejection, GET-with-op
rejection, eval responses, session persistence, custom cookie names, and
custom nREPL handlers.

Author: bbatsov

test/drawbridge/core_test.clj

@@ -0,0 +1,113 @@
+(ns drawbridge.core-test
+  (:require [clojure.string :as str]
+            [clojure.test :refer [are deftest is testing]]
+            [cheshire.core :as json]
+            [drawbridge.core :as drawbridge]
+            [nrepl.transport :as transport]
+            [ring.middleware.keyword-params :refer [wrap-keyword-params]]
+            [ring.middleware.nested-params :refer [wrap-nested-params]]
+            [ring.middleware.params :refer [wrap-params]]))
+
+(defn- make-handler
+  [& opts]
+  (-> (apply drawbridge/ring-handler opts)
+      wrap-keyword-params
+      wrap-nested-params
+      wrap-params))
+
+(defn- parse-body
+  [body]
+  (json/parse-string (apply str body) true))
+
+(defn- encode-params [params]
+  (str/join "&" (map (fn [[k v]]
+                       (str (name k) "=" (java.net.URLEncoder/encode (str v) "UTF-8")))
+                     params)))
+
+(defn- request
+  [method & [params headers]]
+  (let [qs (when (seq params) (encode-params params))]
+    (cond-> {:request-method method
+             :uri "/repl"
+             :headers (or headers {})}
+      (and (= method :get) qs)
+      (assoc :query-string qs)
+
+      (= method :post)
+      (-> (assoc :body (java.io.ByteArrayInputStream.
+                        (.getBytes (or qs "") "UTF-8")))
+          (assoc-in [:headers "content-type"] "application/x-www-form-urlencoded")))))
+
+(defn- get-set-cookie [response]
+  (let [v (get-in response [:headers "Set-Cookie"])]
+    (cond
+      (string? v) v
+      (sequential? v) (str/join "; " v))))
+
+(defn- extract-session-cookie [response cookie-name]
+  (some->> (get-set-cookie response)
+           (re-find (re-pattern (str cookie-name "=([^;]+)")))
+           second))
+
+(deftest method-rejection
+  (let [handler (make-handler)]
+    (testing "unsupported methods return 405 with illegal method error"
+      (are [method] (let [resp (handler (request method))
+                          body (json/parse-string (:body resp) true)]
+                      (and (= 405 (:status resp))
+                           (= "Method Not Allowed" (:error body))
+                           (re-find #"Only GET and POST" (:reason body))))
+        :put :delete :patch))
+
+    (testing "GET with an op parameter returns 405"
+      (let [resp (handler (request :get {:op "eval" :code "(+ 1 2)"}))
+            body (json/parse-string (:body resp) true)]
+        (is (= 405 (:status resp)))
+        (is (= "Method Not Allowed" (:error body)))
+        (is (re-find #"POST request method" (:reason body)))))))
+
+(deftest ring-handler-responses
+  (testing "GET returns empty response array"
+    (let [handler (make-handler)
+          resp (handler (request :get))]
+      (is (= 200 (:status resp)))
+      (is (= [] (parse-body (:body resp))))))
+
+  (testing "POST eval returns result"
+    (let [handler (make-handler :default-read-timeout 5000)
+          resp (handler (request :post {:op "eval" :code "(+ 1 2)"}))
+          messages (parse-body (:body resp))]
+      (is (= 200 (:status resp)))
+      (is (some #(= "3" (:value %)) messages)))))
+
+(deftest session-handling
+  (testing "session cookie is set and can be reused"
+    (let [handler (make-handler :default-read-timeout 5000)
+          cookie-name "drawbridge-session"
+          resp1 (handler (request :post {:op "eval" :code "(+ 10 20)"}))
+          cookie (extract-session-cookie resp1 cookie-name)]
+      (is (some? cookie) "Session cookie should be set")
+      (let [resp2 (handler (-> (request :get)
+                               (assoc-in [:headers "cookie"]
+                                         (str cookie-name "=" cookie))))]
+        (is (= 200 (:status resp2))))))
+
+  (testing "custom cookie name is used in Set-Cookie header"
+    (let [handler (make-handler :cookie-name "my-session")
+          resp (handler (request :get))
+          set-cookie (get-set-cookie resp)]
+      (is (some? set-cookie))
+      (is (re-find #"my-session=" set-cookie)))))
+
+(deftest custom-nrepl-handler
+  (testing "responses come from the supplied handler"
+    (let [marker "custom-handler-marker"
+          custom-handler (fn [msg]
+                           (transport/send (:transport msg)
+                                           {:status :done :value marker}))
+          handler (make-handler :nrepl-handler custom-handler
+                                :default-read-timeout 5000)
+          resp (handler (request :post {:op "eval" :code "ignored"}))
+          messages (parse-body (:body resp))]
+      (is (= 200 (:status resp)))
+      (is (some #(= marker (:value %)) messages)))))