Sync: re-write grade-school (#1050)

* Sync: re-write grade-school

* Add prerequisites

* Change type to any

Author: jiegillet

config.json

@@ -1303,6 +1303,8 @@
         "name": "Grade School",
         "uuid": "4e6d3ddf-b696-40dc-ba02-ed998e595be7",
         "prerequisites": [
+          "atoms",
+          "tuples",
           "lists",
           "maps",
           "enum"

exercises/practice/grade-school/.meta/config.json

@@ -12,6 +12,7 @@
     "devonestes",
     "drueck",
     "elasticdog",
+    "jiegillet",
     "jinyeow",
     "kytrinyx",
     "lpil",

exercises/practice/grade-school/.meta/example.ex

@@ -1,19 +1,48 @@
 defmodule School do
-  def add(db, name, grade) do
-    if name in List.flatten(Map.values(db)) do
-      db
+  @moduledoc """
+  Simulate students in a school.
+
+  Each student is in a grade.
+  """
+
+  @type school :: map
+
+  @doc """
+  Create a new, empty school.
+  """
+  @spec new() :: school
+  def new(), do: %{}
+
+  @doc """
+  Add a student to a particular grade in school.
+  """
+  @spec add(school, String.t(), integer) :: {:ok | :error, school}
+  def add(school, name, grade) do
+    if name in List.flatten(Map.values(school)) do
+      {:error, school}
     else
-      Map.update(db, grade, [name], &[name | &1])
+      {:ok, Map.update(school, grade, [name], &[name | &1])}
     end
   end
 
-  def grade(db, grade) do
-    Map.get(db, grade, [])
+  @doc """
+  Return the names of the students in a particular grade, sorted alphabetically.
+  """
+  @spec grade(school, integer) :: [String.t()]
+  def grade(school, grade) do
+    Map.get(school, grade, [])
+    |> Enum.sort()
   end
 
-  def sort(db) do
-    db
-    |> Enum.map(fn {k, v} -> {k, Enum.sort(v)} end)
+  @doc """
+  Return the names of all the students in the school sorted by grade and name.
+  """
+  @spec roster(school) :: [String.t()]
+  def roster(school) do
+    school
+    |> Enum.map(fn {grade, students} -> {grade, Enum.sort(students)} end)
     |> Enum.sort()
+    |> Enum.map(fn {_grade, students} -> students end)
+    |> Enum.concat()
   end
 end

exercises/practice/grade-school/.meta/tests.toml

@@ -9,35 +9,78 @@
 # As user-added comments (using the # character) will be removed when this file
 # is regenerated, comments can be added via a `comment` key.
 
+[a3f0fb58-f240-4723-8ddc-e644666b85cc]
+description = "Roster is empty when no student is added"
+
+[9337267f-7793-4b90-9b4a-8e3978408824]
+description = "Add a student"
+
 [6d0a30e4-1b4e-472e-8e20-c41702125667]
-description = "Adding a student adds them to the sorted roster"
+description = "Student is added to the roster"
+
+[73c3ca75-0c16-40d7-82f5-ed8fe17a8e4a]
+description = "Adding multiple students in the same grade in the roster"
+
+[233be705-dd58-4968-889d-fb3c7954c9cc]
+description = "Multiple students in the same grade are added to the roster"
+
+[87c871c1-6bde-4413-9c44-73d59a259d83]
+description = "Cannot add student to same grade in the roster more than once"
 
 [c125dab7-2a53-492f-a99a-56ad511940d8]
 description = "A student can't be in two different grades"
 include = false
 
 [a0c7b9b8-0e89-47f8-8b4a-c50f885e79d1]
 description = "A student can only be added to the same grade in the roster once"
+include = false
 reimplements = "c125dab7-2a53-492f-a99a-56ad511940d8"
 
-[233be705-dd58-4968-889d-fb3c7954c9cc]
-description = "Adding more students adds them to the sorted roster"
+[d7982c4f-1602-49f6-a651-620f2614243a]
+description = "Student not added to same grade in the roster more than once"
+reimplements = "a0c7b9b8-0e89-47f8-8b4a-c50f885e79d1"
+
+[e70d5d8f-43a9-41fd-94a4-1ea0fa338056]
+description = "Adding students in multiple grades"
 
 [75a51579-d1d7-407c-a2f8-2166e984e8ab]
-description = "Adding students to different grades adds them to the same sorted roster"
+description = "Students in multiple grades are added to the roster"
+
+[7df542f1-57ce-433c-b249-ff77028ec479]
+description = "Cannot add same student to multiple grades in the roster"
 
 [6a03b61e-1211-4783-a3cc-fc7f773fba3f]
 description = "A student cannot be added to more than one grade in the sorted roster"
+include = false
 reimplements = "c125dab7-2a53-492f-a99a-56ad511940d8"
 
-[a3f0fb58-f240-4723-8ddc-e644666b85cc]
-description = "Roster returns an empty list if there are no students enrolled"
+[c7ec1c5e-9ab7-4d3b-be5c-29f2f7a237c5]
+description = "Student not added to multiple grades in the roster"
+reimplements = "6a03b61e-1211-4783-a3cc-fc7f773fba3f"
 
-[180a8ff9-5b94-43fc-9db1-d46b4a8c93b6]
-description = "Student names with grades are displayed in the same sorted roster"
+[d9af4f19-1ba1-48e7-94d0-dabda4e5aba6]
+description = "Students are sorted by grades in the roster"
 
-[1bfbcef1-e4a3-49e8-8d22-f6f9f386187e]
-description = "Grade returns the students in that grade in alphabetical order"
+[d9fb5bea-f5aa-4524-9d61-c158d8906807]
+description = "Students are sorted by name in the roster"
+
+[180a8ff9-5b94-43fc-9db1-d46b4a8c93b6]
+description = "Students are sorted by grades and then by name in the roster"
 
 [5e67aa3c-a3c6-4407-a183-d8fe59cd1630]
-description = "Grade returns an empty list if there are no students in that grade"
+description = "Grade is empty if no students in the roster"
+
+[1e0cf06b-26e0-4526-af2d-a2e2df6a51d6]
+description = "Grade is empty if no students in that grade"
+
+[2bfc697c-adf2-4b65-8d0f-c46e085f796e]
+description = "Student not added to same grade more than once"
+
+[66c8e141-68ab-4a04-a15a-c28bc07fe6b9]
+description = "Student not added to multiple grades"
+
+[c9c1fc2f-42e0-4d2c-b361-99271f03eda7]
+description = "Student not added to other grade for multiple grades"
+
+[1bfbcef1-e4a3-49e8-8d22-f6f9f386187e]
+description = "Students are sorted by name in a grade"

exercises/practice/grade-school/lib/school.ex

@@ -5,24 +5,33 @@ defmodule School do
   Each student is in a grade.
   """
 
+  @type school :: any()
+
+  @doc """
+  Create a new, empty school.
+  """
+  @spec new() :: school
+  def new() do
+  end
+
   @doc """
   Add a student to a particular grade in school.
   """
-  @spec add(map, String.t(), integer) :: map
-  def add(db, name, grade) do
+  @spec add(school, String.t(), integer) :: {:ok | :error, school}
+  def add(school, name, grade) do
   end
 
   @doc """
-  Return the names of the students in a particular grade.
+  Return the names of the students in a particular grade, sorted alphabetically.
   """
-  @spec grade(map, integer) :: [String.t()]
-  def grade(db, grade) do
+  @spec grade(school, integer) :: [String.t()]
+  def grade(school, grade) do
   end
 
   @doc """
-  Sorts the school by grade and name.
+  Return the names of all the students in the school sorted by grade and name.
   """
-  @spec sort(map) :: [{integer, [String.t()]}]
-  def sort(db) do
+  @spec roster(school) :: [String.t()]
+  def roster(school) do
   end
 end

exercises/practice/grade-school/test/school_test.exs

@@ -1,88 +1,133 @@
 defmodule SchoolTest do
   use ExUnit.Case
 
-  @db %{}
+  def make_school_with_students(students) do
+    {results, school} =
+      Enum.reduce(students, {[], School.new()}, fn {student, grade}, {results, school} ->
+        {result, school} = School.add(school, student, grade)
+        {[result | results], school}
+      end)
+
+    {Enum.reverse(results), school}
+  end
 
-  test "add student" do
-    actual = School.add(@db, "Aimee", 2)
-    assert actual == %{2 => ["Aimee"]}
+  # @tag :pending
+  test "Roster is empty when no student is added" do
+    assert School.roster(School.new()) == []
   end
 
-  test "a student can only be added to the same grade once" do
-    actual =
-      @db
-      |> School.add("Aimee", 2)
-      |> School.add("Aimee", 2)
+  @tag :pending
+  test "Add a student" do
+    {result, school} = School.add(School.new(), "Aimee", 2)
 
-    assert actual == %{2 => ["Aimee"]}
+    assert result == :ok
+    assert School.roster(school) == ["Aimee"]
   end
 
-  test "a student cannot be added to more than one grade" do
-    actual =
-      @db
-      |> School.add("Aimee", 2)
-      |> School.add("Aimee", 1)
+  @tag :pending
+  test "Adding multiple students in the same grade in the roster" do
+    students = [{"Blair", 2}, {"James", 2}, {"Paul", 2}]
+    {results, school} = make_school_with_students(students)
 
-    assert actual == %{2 => ["Aimee"]}
+    assert results == [:ok, :ok, :ok]
+    assert School.roster(school) == ["Blair", "James", "Paul"]
   end
 
   @tag :pending
-  test "add more students in same class" do
-    actual =
-      @db
-      |> School.add("James", 2)
-      |> School.add("Blair", 2)
-      |> School.add("Paul", 2)
-
-    assert Enum.sort(actual[2]) == ["Blair", "James", "Paul"]
+  test "Cannot add student to same grade in the roster more than once" do
+    students = [{"Blair", 2}, {"James", 2}, {"James", 2}, {"Paul", 2}]
+    {results, school} = make_school_with_students(students)
+
+    assert results == [:ok, :ok, :error, :ok]
+    assert School.roster(school) == ["Blair", "James", "Paul"]
   end
 
   @tag :pending
-  test "add students to different grades" do
-    actual =
-      @db
-      |> School.add("Chelsea", 3)
-      |> School.add("Logan", 7)
+  test "Adding students in multiple grades" do
+    students = [{"Chelsea", 3}, {"Logan", 7}]
+    {results, school} = make_school_with_students(students)
 
-    assert actual == %{3 => ["Chelsea"], 7 => ["Logan"]}
+    assert results == [:ok, :ok]
+    assert School.roster(school) == ["Chelsea", "Logan"]
   end
 
   @tag :pending
-  test "get students in a grade" do
-    actual =
-      @db
-      |> School.add("Bradley", 5)
-      |> School.add("Franklin", 5)
-      |> School.add("Jeff", 1)
-      |> School.grade(5)
-
-    assert Enum.sort(actual) == ["Bradley", "Franklin"]
+  test "Cannot add same student to multiple grades in the roster" do
+    students = [{"Blair", 2}, {"James", 2}, {"James", 3}, {"Paul", 3}]
+    {results, school} = make_school_with_students(students)
+
+    assert results == [:ok, :ok, :error, :ok]
+    assert School.roster(school) == ["Blair", "James", "Paul"]
   end
 
   @tag :pending
-  test "get students in a non existent grade" do
-    assert [] == School.grade(@db, 1)
+  test "Students are sorted by grades in the roster" do
+    students = [{"Jim", 3}, {"Peter", 2}, {"Anna", 1}]
+    {_results, school} = make_school_with_students(students)
+
+    assert School.roster(school) == ["Anna", "Peter", "Jim"]
   end
 
   @tag :pending
-  test "sort school by grade and by student name" do
-    actual =
-      @db
-      |> School.add("Peter", 2)
-      |> School.add("Anna", 1)
-      |> School.add("Barb", 1)
-      |> School.add("Zoe", 2)
-      |> School.add("Alex", 2)
-      |> School.add("Jim", 3)
-      |> School.add("Charlie", 1)
-      |> School.sort()
-
-    expected = [
-      {1, ["Anna", "Barb", "Charlie"]},
-      {2, ["Alex", "Peter", "Zoe"]},
-      {3, ["Jim"]}
+  test "Students are sorted by name in the roster" do
+    students = [{"Peter", 2}, {"Zoe", 2}, {"Alex", 2}]
+    {_results, school} = make_school_with_students(students)
+
+    assert School.roster(school) == ["Alex", "Peter", "Zoe"]
+  end
+
+  @tag :pending
+  test "Students are sorted by grades and then by name in the roster" do
+    students = [
+      {"Peter", 2},
+      {"Anna", 1},
+      {"Barb", 1},
+      {"Zoe", 2},
+      {"Alex", 2},
+      {"Jim", 3},
+      {"Charlie", 1}
     ]
 
-    assert expected == actual
+    {_results, school} = make_school_with_students(students)
+
+    assert School.roster(school) == ["Anna", "Barb", "Charlie", "Alex", "Peter", "Zoe", "Jim"]
+  end
+
+  @tag :pending
+  test "Grade is empty if no students in the roster" do
+    assert School.grade(School.new(), 1) == []
+  end
+
+  @tag :pending
+  test "Grade is empty if no students in that grade" do
+    students = [{"Peter", 2}, {"Zoe", 2}, {"Alex", 2}, {"Jim", 3}]
+    {_results, school} = make_school_with_students(students)
+
+    assert School.grade(school, 1) == []
+  end
+
+  @tag :pending
+  test "Student not added to same grade more than once" do
+    students = [{"Blair", 2}, {"James", 2}, {"James", 2}, {"Paul", 2}]
+    {_results, school} = make_school_with_students(students)
+
+    assert School.roster(school) == ["Blair", "James", "Paul"]
+  end
+
+  @tag :pending
+  test "Student not added to multiple grades" do
+    students = [{"Blair", 2}, {"James", 2}, {"James", 3}, {"Paul", 3}]
+    {_results, school} = make_school_with_students(students)
+
+    assert School.grade(school, 2) == ["Blair", "James"]
+    assert School.grade(school, 3) == ["Paul"]
+  end
+
+  @tag :pending
+  test "Students are sorted by name in a grade" do
+    students = [{"Franklin", 5}, {"Bradley", 5}, {"Jeff", 1}]
+    {_results, school} = make_school_with_students(students)
+
+    assert School.grade(school, 5) == ["Bradley", "Franklin"]
   end
 end