character_counter_test.rb

require 'minitest'
require_relative 'character_counter'


class CharCounterTest < Minitest::Test

  def test_class_exists
    assert CharCounter
  end

  def test_initializes_without_input
    assert CharCounter.new
  end

  def test_initializes_with_string_input
    assert CharCounter.new("hello")
  end

  def test_can_access_string_input
    char_counter = CharCounter.new("hello")
    assert_equal "hello", char_counter.string
  end

  def test_without_input_input_is_nil
    char_counter = CharCounter.new
    refute char_counter.string
  end

  def test_initializes_with_result
    char_counter = CharCounter.new
    assert char_counter.result
  end

  def test_result_initializes_as_empty_hash
    char_counter = CharCounter.new
    assert_equal({}, char_counter.result)
  end

  def test_letter_count_method_exists
    char_counter = CharCounter.new
    assert char_counter.respond_to?(:letter_count)
  end

  def test_counts_single_letter
    char_counter = CharCounter.new("a")
    char_counter.letter_count
    expected = {'a' => 1}

    assert_equal expected, char_counter.result
  end

  def test_counts_a_second_single_letter
    char_counter = CharCounter.new("b")
    char_counter.letter_count
    expected = {'b' => 1}

    assert_equal expected, char_counter.result
  end

  def test_counts_pair_of_identical_letters
    char_counter = CharCounter.new("aa")
    char_counter.letter_count
    expected = {'a' => 2}

    assert_equal expected, char_counter.result

  end

  def test_counts_pair_of_distinct_letter
    char_counter = CharCounter.new("ab")
    char_counter.letter_count
    expected = {'a' => 1, 'b' => 1}

    assert_equal expected, char_counter.result
  end

  def test_can_count_letters_in_string
    char_counter = CharCounter.new("hello")
    char_counter.letter_count
    expected = {'h'=> 1, 'e' => 1, 'l' => 2, 'o' => 1}
    computed = char_counter.result
    assert_equal expected, computed
  end

  def test_it_outputs_letter_count_in_correct_format
    char_counter = CharCounter.new("hello")
    char_counter.letter_count
    expected = " h: 1\n e: 1\n l: 2\n o: 1\n"

    assert_equal expected, char_counter.print_out
  end

end