Add GradeSchool example and test

GradeSchool/GradeSchoolExample.elm

@@ -0,0 +1,31 @@
+module GradeSchoolExample where
+
+import Dict exposing (..)
+import Result exposing (toMaybe)
+-- TODO: implement these classes
+-- type Grade = Int
+-- type Student = String
+-- type School = Dict Int List String
+
+schoolFromList : List (Int, String) -> Dict Int (List String)
+schoolFromList schoolList = List.foldl (\tuple -> \dict -> addStudent (fst tuple) (snd tuple) dict)
+  newSchool schoolList
+
+schoolToList : Dict Int (List String) -> List (Int, List String)
+schoolToList school = Dict.toList school
+
+newSchool : Dict Int (List String)
+newSchool = Dict.empty
+
+addStudent : Int -> String -> Dict Int (List String) -> Dict Int (List String)
+addStudent grade student school =
+  Dict.insert grade (List.sort (student :: (studentsInGrade grade school))) school
+
+gradeWithStudents : Int -> List String -> Dict Int (List String)
+gradeWithStudents grade students = Dict.singleton grade (List.sort students)
+
+studentsInGrade : Int -> Dict Int (List String) -> List String
+studentsInGrade grade school =
+  case (Dict.get grade school) of
+    Just list -> list
+    Nothing -> []

GradeSchool/GradeSchoolTest.elm

@@ -0,0 +1,31 @@
+module GradeSchoolTest where
+
+-- TODO - remove example inclusion once Problem sets are ready to go live or CI is set up.
+
+-- import GradeSchoolExample exposing (addStudent,
+--   newSchool, gradeWithStudents, schoolFromList,
+--   studentsInGrade, schoolToList)
+
+import GradeSchoolExample as S exposing (..)
+
+import ElmTest.Test exposing (test, Test, suite)
+import ElmTest.Assertion exposing (assert, assertEqual)
+import ElmTest.Runner.Element exposing (runDisplay)
+
+import Dict
+
+tests : Test
+tests = suite "GradeSchool Test Suite"
+        [
+        test "add student" (assertEqual [(2, ["Aimee"])]
+          (S.schoolToList (S.addStudent 2 "Aimee" S.newSchool))),
+        test "add more students in same class" (assertEqual [(2, ["Blair", "James", "Paul"])]
+          (S.schoolToList (S.gradeWithStudents 2 ["James", "Blair", "Paul"]))),
+        test "add students to different grades" (assertEqual [(3, ["Chelsea"]), (7, ["Logan"])]
+          (S.schoolToList (S.schoolFromList [(3, "Chelsea"), (7, "Logan")]))),
+        test "get students in a grade" (assertEqual ["Bradley", "Franklin"]
+          (S.studentsInGrade 5 (S.schoolFromList [(5, "Franklin"), (5, "Bradley"), (1, "Jeff")]))),
+        test "get students in a non-existent grade" (assertEqual [] (S.studentsInGrade 1 S.newSchool))
+        ]
+
+main = runDisplay tests

elm-package.json

@@ -27,7 +27,8 @@
         "SpaceAge",
         "Anagram",
         "NucleotideCount",
-        "PhoneNumber"
+        "PhoneNumber",
+        "GradeSchool"
     ],
     "exposed-modules": [],
     "dependencies": {