Question

Having a rfq model in the app. There are two fields. One is need_report which is a boolean. Another one is report_language which is a string. The logic is if need_report is true, then there should be an entry in report_language. Otherwise, if need_report if false, report_language could be empty. Here is the code in rfq.rb:

  validates :need_report, :presence => true
  validates_inclusion_of :need_report, :in => [true, false]  
  validates :report_language, :presence => {:if => :need_report?}

  def need_report?
    need_report
  end

However the following rspec case failed:

  it "should be OK for nil report_language if need_report is false" do
    rfq = Factory.build(:rfq, :need_report => false, :report_language => nil)
    rfq.should be_valid    
  end

The error is that the rfq is not valid:

  1) Rfq should be OK for nil report_language if need_report is false
     Failure/Error: rfq.should be_valid
       expected valid? to return true, got false
     # ./spec/models/rfq_spec.rb:57:in `block (2 levels) in <top (required)>'

This case could pass if “validates :need_report, :presence => true” is removed from the model. It seems that if need_report is true, then report_language can not be empty.

Any thoughts about the problem? Thanks.

Answer 1

You can’t use validates_presence_of or validates :column, :presence => true to check if boolean columns are empty.

http://api.rubyonrails.org/classes/ActiveModel/Validations/HelperMethods.html#method-i-validates_presence_of

Answer: Instead you need to use validates_inclusion_of and specify an array of accepted inputs, which you already have. This should be sufficient validation for what you want to do.

Explanation: Your first validation is seeing false in the column (which, in Ruby is equivalent to nil). It then runs .blank? on nil and gets back true (false == nil & nil.blank? == true), meaning it thinks the column is blank and it throws an error.