begin adding tests

project.clj

@@ -13,4 +13,5 @@
                  [com.amazonaws/aws-java-sdk "1.6.3"]
                  [overtone/at-at "1.2.0"]
                  [clj-time "0.6.0"]]
+  :profiles {:dev {:dependencies [[midje "1.5.1"]]}}
   :main cmcarthur.doppler.core)

src/cmcarthur/doppler/core.clj

@@ -16,8 +16,9 @@
         reducer (:reducer config)
         metrics (:metrics config)
         output (:output config)
-        value-to-push (apply reducer (map (comp mapper cloudwatch/get-metric) metrics))]
-    (cloudwatch/push-metric output value-to-push)))
+        value-to-push (reduce reducer (map (comp mapper cloudwatch/get-metric) metrics))]
+    (cloudwatch/push-metric output value-to-push)
+    value-to-push))
 
 (defn generate-metrics-from-config
   [config]

test/cmcarthur/doppler/core_test.clj

@@ -0,0 +1,30 @@
+(ns cmcarthur.doppler.core-test
+  (:use midje.sweet)
+  (:require [cmcarthur.doppler.core :refer :all]
+            [cmcarthur.doppler.cloudwatch :as cloudwatch]))
+
+(facts "generate-metric-results"
+  (prerequisites
+    (cloudwatch/get-metric 1) => [{:average 1 :sum 1 :time nil}]
+    (cloudwatch/get-metric 2) => [{:average 2 :sum 2 :time nil}]
+    (cloudwatch/push-metric anything anything) => nil)
+  (fact "uses map-reduce"
+    (generate-metric-results {:mapper (comp :average first)
+                              :reducer +
+                              :metrics [1 2]
+                              :output nil}) => 3)
+  (fact "maintains ordering"
+    (generate-metric-results {:mapper (comp :average first)
+                              :reducer -
+                              :metrics [1 2]
+                              :output nil}) => -1)
+  (fact "can handle more than two metrics"
+    (generate-metric-results {:mapper (comp :average first)
+                              :reducer -
+                              :metrics [1 2 2]
+                              :output nil}) => -3)
+  (fact "works with custom reducers"
+    (generate-metric-results {:mapper (comp :average first)
+                              :reducer (fn [x y] (+ x y))
+                              :metrics [1 2 2]
+                              :output nil}) => 5))