Rails rspec 应该使用匹配器验证不区分大小写的项目失败的唯一性吗？

Question

I'm trying to be a good rails developer and write tests as I go. I've run into something I'm unclear on and am looking for advice. I have a model that has a unique case insensitive attribute. The test is failing however. Whats the correct way to test this? What am I doing wrong?

class Tenant < ApplicationRecord
  validates :name, presence: true
  validates :name, uniqueness: { case_sensitive: false }
end

RSpec.describe Tenant, type: :model do
  it { should validate_presence_of :name }
  it { should validate_uniqueness_of(:name).case_insensitive }
end

It seems like it's trying to set the id as nil even though we have another validation that requires the presence. But why is it doing that while testing name? I'm confused.

Test shows the following result;

Failures:

 1) Tenant Validates Uniqueness of should validate that :name is case-insensitively unique
 Failure/Error: self.id = self.id.downcase

 NoMethodError:
   undefined method `downcase' for nil:NilClass
 # ./app/models/tenant.rb:17:in `block in <class:Tenant>'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validator.rb:96:in `perform_validation'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validator.rb:89:in `validation_result'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validator.rb:85:in `validation_error_messages'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validator.rb:64:in `messages'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validator.rb:25:in `has_messages?'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validator.rb:55:in `messages_match?'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validator.rb:21:in `call'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/allow_value_matcher/attribute_setters_and_validators.rb:38:in `matches?'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/allow_value_matcher/attribute_setters_and_validators.rb:24:in `each'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/allow_value_matcher/attribute_setters_and_validators.rb:24:in `detect'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/allow_value_matcher/attribute_setters_and_validators.rb:24:in `first_passing'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/allow_value_matcher.rb:533:in `public_send'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/allow_value_matcher.rb:533:in `run'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/allow_value_matcher.rb:400:in `does_not_match?'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/disallow_value_matcher.rb:32:in `matches?'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validation_matcher.rb:155:in `run_allow_or_disallow_matcher'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_model/validation_matcher.rb:93:in `disallows_value_of'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb:606:in `validate_two_records_with_same_non_blank_value_cannot_coexist?'
 # /Users/a/.rvm/gems/ruby-2.5.0/gems/shoulda-matchers-3.1.2/lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb:330:in `matches?'
 # ./spec/models/tenant_spec.rb:49:in `block (3 levels) in <top (required)>'

 Finished in 0.09495 seconds (files took 1.89 seconds to load)
 2 examples, 1 failure

 Failed examples:

 rspec ./spec/models/tenant_spec.rb:49 # Tenant Validates Uniqueness of should validate that :name is case-insensitively unique

Note: this is likely something dumb and obvious that I'm just missing. Your help/advice is appreciated.

Versions: Ruby 2.50 :: Rails 5.14 :: Rspec 3.7 :: Shoulda-matcher 3.12

Answer 1

As nattfodd mentions :

It seems you have some before/after hooks defined. Please show more code of Tenant model class.

It was a beforehook that was the issue.