Use string comparisons for better spec failure messages

example_spec.rb

describe Person do
  describe "#billable" do
    it "returns people with a billable role" do
      billable = create(:role, billable: true)
      unbillable = create(:role, billable: false)
      create(:person, name: "BillableOne", role: billable)
      create(:person, name: "BillableTwo", role: billable)
      create(:person, name: "Unbillable", role: unbillable)

      result = Person.billable

      expect(result.map(&:name)).to match_array(%w(BillableOne BillableTwo))
    end
  end
end

# Failures look like:
# 
#   1) Person#billable returns people with a billable role
#      Failure/Error: expect(result.map(&:name)).to match_array(%w(BillableOne BillableTwo))
#        expected collection contained:  ["BillableTwo", "BillableOne"]
#        actual collection contained:    ["BillableTwo", "Unbillable", "BillableOne"]
#        the extra elements were:        ["Unbillable"]
#      # ./spec/models/person_spec.rb:14:in `block (3 levels) in <top (required)>'

describe Person do
  describe "#billable" do
    it "returns people with a billable role" do
      billable = create(:role, billable: true)
      unbillable = create(:role, billable: false)
      expected_people = [
        create(:person, role: billable),
        create(:person, role: billable)
      ]
      create(:person, role: unbillable)

      result = Person.billable

      expect(result).to match_array(expected_people)
    end
  end
end

# Failures look like:
#
#  1) Person#billable returns people with a billable role
#     Failure/Error: expect(result).to match_array(expected_people)
#       expected collection contained:  [#<Person id: 6, name: "Name 1", role_id: 4, location_id: nil, manager_id: nil, salary: 0>, #<Person id: 7, name: "Name 2", role_id: 4, location_id: nil, manager_id: nil, salary: 0>]
#       actual collection contained:    [#<Person id: 6, name: "Name 1", role_id: 4, location_id: nil, manager_id: nil, salary: 0>, #<Person id: 7, name: "Name 2", role_id: 4, location_id: nil, manager_id: nil, salary: 0>, #<Person id: 8, name: "Name 3", role_id: 5, location_id: nil, manager_id: nil, salary: 0>]
#       the extra elements were:        [#<Person id: 8, name: "Name 3", role_id: 5, location_id: nil, manager_id: nil, salary: 0>]
#     # ./spec/models/person_spec.rb:16:in `block (3 levels) in <top (required)>'