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Testing Controller Load Hook Implementation in Devise

This test suite validates Devise’s controller load hooks functionality, ensuring proper method definition and execution during the controller loading process. It specifically tests the ActiveSupport load hook mechanism within Devise controllers.

Test Coverage Overview

The test suite focuses on verifying the proper implementation of ActiveSupport load hooks in Devise controllers.

Key areas covered include:

Dynamic method definition through load hooks
Verification of method presence in controller instance methods
Proper cleanup through method undefined in teardown

Implementation Analysis

The testing approach utilizes Devise’s ControllerTestCase framework to validate load hook behavior. It implements a setup-test-teardown pattern, dynamically defining methods during setup and cleaning them up afterward.

The test leverages ActiveSupport’s on_load mechanism to inject methods into Devise controllers at runtime, demonstrating the framework’s extensibility.

Technical Details

Testing components include:

Devise::ControllerTestCase as the base test class
ActiveSupport load hooks for dynamic method injection
Ruby metaprogramming for method definition and cleanup
Instance method verification through assertion checks

Best Practices Demonstrated

The test exhibits several testing best practices:

Proper test isolation through setup and teardown blocks
Clear separation of concerns between test setup and assertions
Effective cleanup of modified controller state
Focused test scope with single responsibility

heartcombo/devise

test/controllers/load_hooks_controller_test.rb

            
# frozen_string_literal: true

require 'test_helper'

class LoadHooksControllerTest < Devise::ControllerTestCase
  setup do
    ActiveSupport.on_load(:devise_controller) do
      define_method :defined_by_load_hook do
        puts 'I am defined dynamically by activesupport load hook'
      end
    end
  end

  teardown do
    DeviseController.class_eval { undef :defined_by_load_hook }
  end

  test 'load hook called when controller is loaded' do
    assert_includes DeviseController.instance_methods, :defined_by_load_hook
  end
end