Update Caesar Analyzers to be case-insensitive and testable.

src/cipher_analytical_machine/caesar_analyzers.clj

@@ -1,5 +1,6 @@
 (ns cipher-analytical-machine.caesar-analyzers
   (:require [cipher-analytical-machine.caesar :as caesar]
+            [clojure.string :as cs]
             [cipher-analytical-machine.cipher-analyzers :as ca])
   (:gen-class))
 
@@ -12,23 +13,36 @@
        (conj acc [key (caesar/decrypt-message ciphertext key symbols)]))
      '() keys)))
 
+(defn get-all-scores
+  "For pairs (key, plaintext) finds scores and return list of pairs [key, score]."
+  [letter-frequences pairs]
+  (map (fn [[key text]]
+         [key (ca/chi-squared-statistic text letter-frequences)])
+       pairs))
+
+(defn get-min-score-pair
+  "For pairs (key, plaintext) finds scores and return list of pairs [key, score]."
+  [pairs]
+  (reduce
+   (fn [[key value] [new-key new-value]]
+     (if (> value new-value) [new-key new-value]
+         [key value]))
+   [0 Double/MAX_VALUE]
+   pairs))
+
 (defn get-key
   "To find the key with frequencies of letters."
   [ciphertext symbols letter-frequences]
   (->> (get-all-texts ciphertext symbols)
-       (map (fn [[key text]]
-              [key (ca/chi-squared-statistic text letter-frequences)]))
-       (reduce
-        (fn [[key value] [new-key new-value]]
-          (if (> value new-value) [new-key new-value]
-               [key value]))
-        [0 Double/MAX_VALUE])
+       (get-all-scores letter-frequences)
+       (get-min-score-pair)
        (first)))
 
 (defn get-plaintext
-  "Return the plaintext from a ciphertext."
+  "Return the plaintext from a ciphertext. The function is case-insensitive."
   [ciphertext symbols letter-frequences]
-  (caesar/decrypt-message ciphertext
-                          (get-key ciphertext symbols letter-frequences)
-                          symbols))
+  (let [ciphertext (cs/lower-case ciphertext)]
+    (caesar/decrypt-message ciphertext
+                            (get-key ciphertext symbols letter-frequences)
+                            symbols)))