Refactor map-deep-merge-missing -> map-apply-defaults; Tests for map-apply-defaults

Needs more tests

src/rss_thread_watch/utils.clj

@@ -41,13 +41,15 @@
   [pred coll]
    (keep-indexed #(when (pred %2) %1) coll))
 
-(defn map-deep-merge-missing
-  "Merges two maps but only keys missing from first map"
-  [m1 m2]
-  (into m1
-        (for [k (keys m2)]
-          (let [val1 (get m1 k)
-                val2 (get m2 k)]
+(defn map-apply-defaults
+  "Apply default values from [defaults] to keys not present in [conf]
+   Order is very important.
+   Thus all missing values from config are replaced by defaults"
+  [conf defaults]
+  (into conf
+        (for [k (keys defaults)]
+          (let [val1 (get conf k)
+                val2 (get defaults k)]
             (if (and (map? val1)
                      (map? val2))
               {k (map-deep-merge-missing val1 val2)}

test/rss_thread_watch/utils_test.clj

@@ -2,11 +2,13 @@
   (:require [clojure.test :refer :all]
             [rss-thread-watch.utils :refer :all]))
 
-(defn first-map {:a :b
-                 :c "c"
-                 
-                 })
+(def first-map {:a :b
+                :c "c"})
+(def empty-map {})
 
 (deftest map-deep-merge-missing-test
-  (testing "Map deep merge missing"
-    (is ())))
+  (testing "Default values in place of missing keys"
+    (is (= first-map (map-apply-defaults first-map empty-map))
+        "No defaults should return conf map unchanged")
+    (is (= first-map (map-apply-defaults empty-map first-map))
+        "Empty map should be completely replaced by defaults")))