Check for bad enum with rspec

Question

Does anyone know how to check for invalid enum responses in rspec? I can check to ensure that the enum isn't nil with no errors but when I check to ensure that a bad enum value doesn't work, I get an error. These are the two specs:

it 'is not valid without question type' do
    expect(build(:question, question_type: nil)).to have(1).errors_on(:question_type)
end

it 'is not valid with a bad question type' do
    expect(build(:question, question_type: :telepathy)).to have(1).errors_on(:question_type)
end

This is what my model looks like:

class Question < ActiveRecord::Base
    enum question_type: [ :multiple_choice ]
    validates :question_type, presence: true

end

This is the error:

 Failure/Error: expect(build(:question, question_type: :telepathy)).to have(1).errors_on(:question_type)
     ArgumentError:
       'telepathy' is not a valid question_type

This is my factory:

FactoryGirl.define do
  factory :question, :class => 'Question' do
    question_type :multiple_choice
  end
end

Thanks for the help!

Answer 1

Your issue is that you need expect to execute the build as a proc to evaluate the result. Do this by changing the parentheses to curly brackets, as described in https://stackoverflow.com/a/21568225/1935918

it 'is not valid with a bad question type' do
  expect { build(:question, question_type: :telepathy) }
    .to raise_error(ArgumentError)
    .with_message(/is not a valid question_type/)
end