Fix the test name.

test/cipher_analytical_machine/symbols/frequencies_test.clj

@@ -3,7 +3,7 @@
    [clojure.test :refer :all]
    [cipher-analytical-machine.symbols.frequencies :refer :all]))
 
-(deftest calculate-char-index-test
+(deftest map-to-string-test
   (let [symbol-map english-letter-frequencies]
     (testing "The map must be converted to 'etaoinsrhldcumfpgwybvkxjqz'"
       (is (= "etaoinsrhldcumfpgwybvkxjqz"