exercism grade_school_test iteration 8

require 'minitest/autorun'
require_relative 'school'

class SchoolTest < MiniTest::Unit::TestCase

  def school
    @school
  end

  def setup
    @school = School.new
  end

  def test_an_empty_school
    assert_equal({}, school.to_hash)
  end

  def test_add_student
    school.add("Aimee", 2)
    assert_equal({2 => ["Aimee"]}, school.to_hash)
  end

  def test_add_more_students_in_same_class
    school.add("Blair", 2)
    school.add("James", 2)
    school.add("Paul", 2)
    assert_equal({2 => ["Blair", "James", "Paul"]}, school.to_hash)
  end

  def test_add_students_to_different_grades
    school.add("Chelsea", 3)
    school.add("Logan", 7)
    assert_equal({3 => ["Chelsea"], 7 => ["Logan"]}, school.to_hash)
  end

  def test_get_students_in_a_grade
    school.add("Bradley", 5)
    school.add("Franklin", 5)
    school.add("Jeff", 1)
    assert_equal ["Bradley", "Franklin"], school.grade(5)
  end

  def test_get_students_sorted_in_a_grade
    school.add("Franklin", 5)
    school.add("Bradley", 5)
    school.add("Jeff", 1)
    assert_equal ["Bradley", "Franklin"], school.grade(5)
  end

  def test_get_students_in_a_non_existant_grade
    assert_equal [], school.grade(1)
  end

  def test_sort_school
    school.add("Jennifer", 4)
    school.add("Kareem", 6)
    school.add("Christopher", 4)
    school.add("Kyle", 3)
    sorted = {
      3 => ["Kyle"],
      4 => ["Christopher", "Jennifer"],
      6 => ["Kareem"]
    }
    assert_equal sorted, school.to_hash
    assert_equal [3, 4, 6], school.to_hash.keys
  end

  def test_db_add_student_to_grade_after_looking_at_the_db
    err = ->{ school.db[6] = ["Matilda"] }.must_raise RuntimeError
    err.message.must_match "can't modify frozen Hash"
    school.add("Jennifer", 4)
    assert_equal school.db, {4=>["Jennifer"]}
    assert_equal ["Jennifer"], school.grade(4)
  end

  def test_database_external_mutation
    err = ->{ school.database[6] = ["Matilda"] }.must_raise NoMethodError
    err.message.must_match "private method `database' called"
  end

  def test_sort_doesnt_alter_internal_database
    school.add("Bob", 1)
    school.add("Alice", 1)
    original = { 1 => %w[Bob Alice] }

    school.sort # shouldn't impact sort order of school.db
    assert_equal original, school.db
  end

  def test3
    school = School.new
    school.add "James", 2
    x = school.db
    err = ->{ x[2] << "Brian" }.must_raise RuntimeError
    err.message.must_match "can't modify frozen Array"
    assert_equal school.db, {2=>["James"]}
  end
end