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Testing Private Attribute Handling in factory_bot

This test suite examines FactoryBot’s handling of private attributes in Ruby classes. It specifically verifies that attempting to set private attributes through factory definitions raises appropriate errors, ensuring proper encapsulation is maintained.

Test Coverage Overview

The test coverage focuses on validating FactoryBot’s behavior when interacting with private attributes defined in Ruby classes. It tests:

Private attribute accessor handling
Error raising for unauthorized access
Factory definition validation with private members
Class encapsulation enforcement

Implementation Analysis

The testing approach uses RSpec’s expect block syntax to verify error handling. It employs dynamic class definition with a private attr_accessor and attempts to set it through a FactoryBot factory definition, expecting a NoMethodError to be raised when the private setter is accessed.

Technical Details

Testing tools and configuration:

RSpec testing framework
FactoryBot gem for test data generation
Dynamic class definition using define_class helper
Ruby’s private method access controls

Best Practices Demonstrated

The test demonstrates several quality testing practices:

Explicit error expectation testing
Proper isolation of test cases
Clear setup of test prerequisites
Verification of object-oriented principles
Appropriate use of RSpec’s error matching syntax

thoughtbot/factory_bot

spec/acceptance/private_attributes_spec.rb

            
describe "setting private attributes" do
  it "raises a NoMethodError" do
    define_class("User") do
      private

      attr_accessor :foo
    end

    FactoryBot.define do
      factory :user do
        foo { 123 }
      end
    end

    expect {
      FactoryBot.build(:user)
    }.to raise_error NoMethodError, /foo=/
  end
end