我使用的是Rails 4枚举，我想对它们进行适当的测试，所以我为枚举字段设置了以下测试：

it { should validate_inclusion_of(:category).in_array(%w[sale sale_with_tax fees lease tax_free other payroll]) }
it { should validate_inclusion_of(:type).in_array(%w[receivable payable]) }

这是他们正在验证的模型：

class Invoice < ActiveRecord::Base
  belongs_to :user

  enum category: [:sale, :sale_with_tax, :fees, :lease, :tax_free, :other, :payroll]
  enum type: [:receivable, :payable]

  validates :user, presence: true
  validates :issue_date, presence: true
  validates :series, presence: true
  validates :folio, presence: true
  validates :issuing_location, presence: true
  validates :payment_method, presence: true
  validates :last_digits, presence: true
  validates :credit_note, presence: true
  validates :total, presence: true
  validates :subtotal, presence: true
  validates :category, presence: true
  validates_inclusion_of :category, in: Invoice.categories.keys
  validates :type, presence: true
  validates_inclusion_of :type, in: Invoice.types.keys
end

但是当我进行测试时，我得到：

1) Invoice should ensure inclusion of type in [0, 1]
     Failure/Error: it { should validate_inclusion_of(:type).in_array([0,1]) }
     ArgumentError:
       '123456789' is not a valid type
     # ./spec/models/invoice_spec.rb:20:in `block (2 levels) in <top (required)>'

  2) Invoice should ensure inclusion of category in [0, 1, 2, 3, 4, 5, 6]
     Failure/Error: it { should validate_inclusion_of(:category).in_array([0,1,2,3,4,5,6]) }
     ArgumentError:
       '123456789' is not a valid category
     # ./spec/models/invoice_spec.rb:19:in `block (2 levels) in <top (required)>'

我也尝试过在测试数组中使用字符串值，但我得到了同样的错误，我真的不明白它。