caesar3 tests and comments

wk3/src/Caesar3.elm

@@ -8,21 +8,31 @@ import Caesar2 exposing (..)
     Dimitar Byalkov and Kaloyan Stoykov
 -}
 
+-- Start value is 1, so the Brute Generator function can generate all possible decrypted strings
+accumulatorStart: Int
+accumulatorStart = 1
+
+-- End value is 25 => the strings are decrypted with keys 1-25 
+accumulatorEnd: Int
+accumulatorEnd = 25
+
 candidates: List String -> String -> List (Int, String)
 candidates canaries encryptedText =
     case canaries of
         [] ->
             []
         x :: xs ->
-            filterList x (bruteGenerator encryptedText 0) ++ candidates (List.drop 1 canaries) encryptedText
+            filterList x (bruteGenerator encryptedText accumulatorStart) ++ candidates (List.drop 1 canaries) encryptedText
 
+-- The Brute Generator generates all possible decrypted strings from a given start value
 bruteGenerator: String -> Int -> List (Int, String)
 bruteGenerator encryptedText accumulator = 
-    if accumulator < 25 then
+    if accumulator < accumulatorEnd then
         (accumulator, (decrypt accumulator encryptedText)) :: bruteGenerator encryptedText (accumulator + 1)
     else
         List.singleton (accumulator, (decrypt accumulator encryptedText))
-            
+
+-- Filters a given list of tuples' second value by a given key (canary)
 filterList: String -> List (Int, String) -> List (Int, String)
 filterList canary candidateTexts = 
     case candidateTexts of
@@ -38,7 +48,33 @@ containsText: String -> String -> Bool
 containsText canary text =
     if String.left (String.length canary) text == canary then
         True
+    -- Necessary to prevent a RangeError: Maximum call stack exceeded
     else if String.length text == 0 then
         False
     else
-        containsText canary (String.dropLeft 1 text)
+        containsText canary (String.dropLeft 1 text)
+
+-- Tests
+testContainsText: Bool
+testContainsText =
+    containsText "THE" "OVERTHELAZYDOG"
+
+testContainsTextNot: Bool
+testContainsTextNot =
+    not (containsText "AND" "OVERTHELAZYDOG")
+
+testBruteGenerator: Bool
+testBruteGenerator = 
+    bruteGenerator "AA" 1 == [(1,"ZZ"),(2,"YY"),(3,"XX"),(4,"WW"),(5,"VV"),(6,"UU"),(7,"TT"),(8,"SS"),(9,"RR"),(10,"QQ"),(11,"PP"),(12,"OO"),(13,"NN"),(14,"MM"),(15,"LL"),(16,"KK"),(17,"JJ"),(18,"II"),(19,"HH"),(20,"GG"),(21,"FF"),(22,"EE"),(23,"DD"),(24,"CC"),(25,"BB")]
+
+testFilterList: Bool
+testFilterList = 
+    filterList "THE" (bruteGenerator "BPMYCQKSJZWEVNWF" 0) == [(8,"THEQUICKBROWNFOX")]
+
+testCandidates: Bool
+testCandidates =
+    candidates ["THE", "AND"] "DGGADBCOOCZYMJHZYVMTOJOCZHVS" == [(5, "YBBVYWXJJXUTHECUTQHOJEJXUCQN"), (14,"PSSMPNOAAOLKYVTLKHYFAVAOLTHE"), (21,"ILLFIGHTTHEDROMEDARYTOTHEMAX")]
+
+allCaesar3Tests: List Bool
+allCaesar3Tests =
+    [testContainsText, testContainsTextNot, testBruteGenerator, testFilterList, testCandidates]