Allow spying on multiple protocols

Author: mping

README.md

@@ -240,9 +240,7 @@ to mock multiple protocols.
 ```
 
 You will also find a `spy` macro within the protocol namespace, this
-currently supports spying on an implementation for a single protocol.
-Caution: the protocol `spy` macro will change in the future when I add support for spying on multiple protocols, you can see examples in the 
-`spy.protocol-test` namespace.
+can also be used to spy on multiple protocols: `(spy.protocol/spy Proto1...ProtoN impl)`
 
 ## Contributing
 

src/clj/spy/protocol.clj

@@ -45,20 +45,33 @@
           methods))
 
 (defmacro spy
-  "Reify the protocol, spies attached to the reified object via metadata"
+  "Reify the protocols, spies attached to the reified object via metadata.
+  Can accept multiple protocols at once: (spy.protocol/spy Proto1...ProtoN impl)"
   {:style/indent [:defn [1]]}
-  [protocol instance]
-  (let [methods (vals (protocol-methods @(resolve protocol)))
+  [& args]
+  (let [protocols (butlast args)
+        instance  (last args)
+        proto-methods (reduce (fn [acc protocol]
+                                (assoc acc protocol (vals (protocol-methods @(resolve protocol)))))
+                              {}
+                              protocols)
+        all-methods (->> proto-methods vals (apply concat))
         spy-fns-sym (gensym "spy-fns-")]
-    `(let [~spy-fns-sym ~(->spy-fns methods instance)]
+
+    `(let [~spy-fns-sym ~(->spy-fns all-methods instance)]
        (with-meta
-         (reify ~protocol
-           ~@(mapcat (fn [{:keys [name arglists]}]
-                       (map (fn [arglist]
-                              (let [args (->args arglist)]
-                                (list name args (concat (list (list (keyword name) spy-fns-sym)) args))))
-                            arglists))
-               methods))
+         ~@(let [protos+impls
+                  (for [[protocol methods] proto-methods]
+                     (concat
+                       (list (symbol protocol))
+                       (mapcat (fn [{:keys [name arglists]}]
+                                 (map (fn [arglist]
+                                        (let [args (->args arglist)]
+                                          (list name args (concat (list (list (keyword name) spy-fns-sym)) args))))
+                                      arglists))
+                               methods)))]
+             (list (concat '(reify)
+                           (apply concat protos+impls))))
          ~spy-fns-sym))))
 
 (defn spies [instance]

test/clj/spy/protocol_test.clj

@@ -100,9 +100,9 @@
         methods (protocol-methods p)]
 
     (is (= {:hello
-           {:name 'hello
-            :arglists [['this 'a] ['this 'a 'b 'c]]
-            :var #'spy.protocol-test/hello}}
+            {:name 'hello
+             :arglists [['this 'a] ['this 'a 'b 'c]]
+             :var #'spy.protocol-test/hello}}
            methods)))
 
   (let [p @(resolve 'spy.protocol-test/AllSorts)
@@ -157,20 +157,40 @@
   (method-b [this x]))
 
 (deftest multi-protocols-test
-  (let [mock (protocol/mock
-               ProtocolA
-               (method-a [this x]
-                 :a)
-
-               ProtocolB
-               (method-b [this x]
-                 :b))]
-    (is (= :a (method-a mock :testing)))
-    (is (= :b (method-b mock :test)))
-    (is (spy/called-once-with? (:method-a (protocol/spies mock))
-                               mock
-                               :testing))
-
-    (is (spy/called-once-with? (:method-b (protocol/spies mock))
-                               mock
-                               :test))))
+  (testing "mock"
+    (let [mock (protocol/mock
+                 ProtocolA
+                 (method-a [this x]
+                   :a)
+
+                 ProtocolB
+                 (method-b [this x]
+                   :b))]
+      (is (= :a (method-a mock :testing)))
+      (is (= :b (method-b mock :test)))
+      (is (spy/called-once-with? (:method-a (protocol/spies mock))
+                                 mock
+                                 :testing))
+
+      (is (spy/called-once-with? (:method-b (protocol/spies mock))
+                                 mock
+                                 :test))))
+  (testing "spy"
+    (let [impl (reify
+                 ProtocolA
+                 (method-a [this x ] :a)
+                 ProtocolB
+                 (method-b [this x] :b))
+          spied (protocol/spy ProtocolA ProtocolB impl)]
+
+      (is (= :a (method-a spied :testing)))
+      (is (= :b (method-b spied :test)))
+
+      (is (spy/called-once-with? (:method-a (protocol/spies spied))
+                                 spied
+                                 :testing))
+
+      (is (spy/called-once-with? (:method-b (protocol/spies spied))
+                                 spied
+                                 :test)))))
+