grade-school

elixir/grade-school/.exercism/config.json

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+{
+  "authors": [
+    "rubysolo"
+  ],
+  "contributors": [
+    "andrewsardone",
+    "angelikatyborska",
+    "bartj3",
+    "Cohen-Carlisle",
+    "dalexj",
+    "devonestes",
+    "drueck",
+    "elasticdog",
+    "jiegillet",
+    "jinyeow",
+    "kytrinyx",
+    "lpil",
+    "neenjaw",
+    "parkerl",
+    "petehuang",
+    "pminten",
+    "sotojuan",
+    "Teapane",
+    "veelenga",
+    "victorlcampos",
+    "waiting-for-dev"
+  ],
+  "files": {
+    "solution": [
+      "lib/school.ex"
+    ],
+    "test": [
+      "test/school_test.exs"
+    ],
+    "example": [
+      ".meta/example.ex"
+    ]
+  },
+  "blurb": "Given students' names along with the grade that they are in, create a roster for the school.",
+  "source": "A pairing session with Phil Battos at gSchool"
+}

elixir/grade-school/.exercism/metadata.json

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+{"track":"elixir","exercise":"grade-school","id":"9161318ecb0e46bc89207b97059c3866","url":"https://exercism.org/tracks/elixir/exercises/grade-school","handle":"negrienko","is_requester":true,"auto_approve":false}

elixir/grade-school/.formatter.exs

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+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

elixir/grade-school/.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+grade_school-*.tar
+

elixir/grade-school/HELP.md

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+# Help
+
+## Running the tests
+
+From the terminal, change to the base directory of the exercise then execute the tests with:
+
+```bash
+$ mix test
+```
+
+This will execute the test file found in the `test` subfolder -- a file ending in `_test.exs`
+
+Documentation:
+
+* [`mix test` - Elixir's test execution tool](https://hexdocs.pm/mix/Mix.Tasks.Test.html)
+* [`ExUnit` - Elixir's unit test library](https://hexdocs.pm/ex_unit/ExUnit.html)
+
+## Pending tests
+
+In test suites of practice exercises, all but the first test have been tagged to be skipped.
+
+Once you get a test passing, you can unskip the next one by commenting out the relevant `@tag :pending` with a `#` symbol.
+
+For example:
+
+```elixir
+# @tag :pending
+test "shouting" do
+  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
+end
+```
+
+If you wish to run all tests at once, you can include all skipped test by using the `--include` flag on the `mix test` command:
+
+```bash
+$ mix test --include pending
+```
+
+Or, you can enable all the tests by commenting out the `ExUnit.configure` line in the file `test/test_helper.exs`.
+
+```elixir
+# ExUnit.configure(exclude: :pending, trace: true)
+```
+
+## Useful `mix test` options
+
+* `test/<FILE>.exs:LINENUM` - runs only a single test, the test from `<FILE>.exs` whose definition is on line `LINENUM`
+* `--failed` - runs only tests that failed the last time they ran
+* `--max-failures` - the suite stops evaluating tests when this number of test failures
+is reached
+* `--seed 0` - disables randomization so the tests in a single file will always be ran
+in the same order they were defined in
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit lib/school.ex` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Elixir track's documentation](https://exercism.org/docs/tracks/elixir)
+- The [Elixir track's programming category on the forum](https://forum.exercism.org/c/programming/elixir)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+If you're stuck on something, it may help to look at some of the [available resources](https://exercism.org/docs/tracks/elixir/resources) out there where answers might be found.

elixir/grade-school/README.md

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+# Grade School
+
+Welcome to Grade School on Exercism's Elixir Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Given students' names along with the grade that they are in, create a roster for the school.
+
+In the end, you should be able to:
+
+- Add a student's name to the roster for a grade
+  - "Add Jim to grade 2."
+  - "OK."
+- Get a list of all students enrolled in a grade
+  - "Which students are in grade 2?"
+  - "We've only got Jim just now."
+- Get a sorted list of all students in all grades.
+  Grades should sort as 1, 2, 3, etc., and students within a grade should be sorted alphabetically by name.
+  - "Who all is enrolled in school right now?"
+  - "Let me think.
+    We have Anna, Barb, and Charlie in grade 1, Alex, Peter, and Zoe in grade 2 and Jim in grade 5.
+    So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe and Jim"
+
+Note that all our students only have one name (It's a small town, what do you want?) and each student cannot be added more than once to a grade or the roster.
+In fact, when a test attempts to add the same student more than once, your implementation should indicate that this is incorrect.
+
+## Source
+
+### Created by
+
+- @rubysolo
+
+### Contributed to by
+
+- @andrewsardone
+- @angelikatyborska
+- @bartj3
+- @Cohen-Carlisle
+- @dalexj
+- @devonestes
+- @drueck
+- @elasticdog
+- @jiegillet
+- @jinyeow
+- @kytrinyx
+- @lpil
+- @neenjaw
+- @parkerl
+- @petehuang
+- @pminten
+- @sotojuan
+- @Teapane
+- @veelenga
+- @victorlcampos
+- @waiting-for-dev
+
+### Based on
+
+A pairing session with Phil Battos at gSchool

elixir/grade-school/lib/school.ex

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+defmodule School do
+  @moduledoc """
+  Simulate students in a school.
+
+  Each student is in a grade.
+  """
+
+  @type school :: any()
+
+  @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 Enum.any?(roster(school), &(&1 == name)) do
+      {:error, school}
+    else
+      {:ok, Map.put(school, grade, [name | Map.get(school, grade, [])])}
+    end
+  end
+
+  @doc """
+  Return the names of the students in a particular grade, sorted alphabetically.
+  """
+  @spec grade(school, integer) :: [String.t()]
+  def grade(school, grade) when not is_map_key(school, grade), do: []
+  def grade(school, grade), do: Enum.sort(Map.get(school, grade))
+
+  @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
+    for grade <- Enum.sort(Map.keys(school)), reduce: [] do
+      acc -> acc ++ grade(school, grade)
+    end
+  end
+end

elixir/grade-school/mix.exs

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+defmodule School.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :school,
+      version: "0.1.0",
+      # elixir: "~> 1.8",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end

elixir/grade-school/test/school_test.exs

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+defmodule SchoolTest do
+  use ExUnit.Case
+
+  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 "Roster is empty when no student is added" do
+    assert School.roster(School.new()) == []
+  end
+
+  test "Add a student" do
+    {result, school} = School.add(School.new(), "Aimee", 2)
+
+    assert result == :ok
+    assert School.roster(school) == ["Aimee"]
+  end
+
+  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 results == [:ok, :ok, :ok]
+    assert School.roster(school) == ["Blair", "James", "Paul"]
+  end
+
+  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
+
+  test "Adding students in multiple grades" do
+    students = [{"Chelsea", 3}, {"Logan", 7}]
+    {results, school} = make_school_with_students(students)
+
+    assert results == [:ok, :ok]
+    assert School.roster(school) == ["Chelsea", "Logan"]
+  end
+
+  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
+
+  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
+
+  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
+
+  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}
+    ]
+
+    {_results, school} = make_school_with_students(students)
+
+    assert School.roster(school) == ["Anna", "Barb", "Charlie", "Alex", "Peter", "Zoe", "Jim"]
+  end
+
+  test "Grade is empty if no students in the roster" do
+    assert School.grade(School.new(), 1) == []
+  end
+
+  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
+
+  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
+
+  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
+
+  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

elixir/grade-school/test/test_helper.exs

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+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)