Red-Green-Refactor by Example Excercise

spec.rb

# Use TDD principles to build out name functionality for a Person.
# Here are the requirements:
# - Add a method to return the full name as a string. A full name includes
#   first, middle, and last name. If the middle name is missing, there shouldn't
#   have extra spaces.
# - Add a method to return a full name with a middle initial. If the middle name
#   is missing, there shouldn't be extra spaces or a period.
# - Add a method to return all initials. If the middle name is missing, the
#   initials should only have two characters.
#
# We've already sketched out the spec descriptions for the #full_name. Try
# building the specs for that method, watch them fail, then write the code to
# make them pass. Then move on to the other two methods, but this time you'll
# create the descriptions to match the requirements above.

class Person
  attr_reader :first_name, :middle_name, :last_name

  def initialize(first_name:, middle_name: :no_name, last_name:)
    @first_name = first_name
    @middle_name = middle_name
    @last_name = last_name
  end

  def full_name
    [first_name, middle_name, last_name]
      .reject { |name| name == :no_name }
      .join(" ")
  end

  def full_name_with_middle_initial
    [first_name, abbreviate(middle_name), last_name]
      .reject { |name| name == :no_name }
      .join(" ")
  end

  def initials
    [first_name, middle_name, last_name]
      .map { |name| initial(name) }
      .reject { |name| name == :no_name }
      .join
  end

  protected

  def abbreviate(name)
    return name if name == :no_name

    initial(name) + "."
  end

  def initial(name)
    return name if name == :no_name

    name.chars.first
  end
end

RSpec.describe Person do
  describe "#full_name" do
    it "concatenates first name, middle name, and last name with spaces" do
      person = Person.new(
        first_name: "John",
        middle_name: "Fitzgerald",
        last_name: "Kennedy"
      )

      expect(person.full_name).to eq "John Fitzgerald Kennedy"
    end

    it "does not add extra spaces if middle name is missing" do
      person = Person.new(
        first_name: "John",
        last_name: "Cena"
      )

      expect(person.full_name).to eq "John Cena"
    end
  end

  describe "#full_name_with_middle_initial" do
    it "abbreviates the middle name" do
      person = Person.new(
        first_name: "John",
        middle_name: "Fitzgerald",
        last_name: "Kennedy"
      )

      expect(person.full_name_with_middle_initial).to eq "John F. Kennedy"
    end

    it "handles missing middle names" do
      person = Person.new(
        first_name: "John",
        last_name: "Cena"
      )

      expect(person.full_name_with_middle_initial).to eq "John Cena"
    end
  end

  describe "#initials" do
    it "returns the initials" do
      person = Person.new(
        first_name: "John",
        middle_name: "Fitzgerald",
        last_name: "Kennedy"
      )

      expect(person.initials).to eq "JFK"
    end

    it "handles missing middle names" do
      person = Person.new(
        first_name: "John",
        last_name: "Cena"
      )

      expect(person.initials).to eq "JC"
    end
  end
end