Back to Repositories

Testing HasAttachedFile Module Implementation in Paperclip

This test suite thoroughly examines the HasAttachedFile module in Paperclip, focusing on attachment definition and validation functionality. It verifies the proper implementation of attachment-related methods, callbacks, and media type validations essential for file handling in Ruby applications.

Test Coverage Overview

The test suite provides comprehensive coverage of the HasAttachedFile module’s core functionality.

Key areas tested include:

Attachment getter and setter method definitions
Attachment query methods and class-level definitions
Validation mechanisms and error handling
Registration with AttachmentRegistry
Lifecycle callbacks implementation
Media type validation configurations

Implementation Analysis

The testing approach employs RSpec with extensive use of stubs and expectations to isolate the tested components.

Notable patterns include:

Custom AttachmentAdder test helper class
Mocha API integration for stubbing
Modular test organization with nested contexts
Behavior-driven development (BDD) style assertions

Technical Details

Testing infrastructure includes:

RSpec as the primary testing framework
Mocha for mocking and stubbing
Custom assertion helpers
Structured test contexts
Isolated class stubs for dependency management

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Isolated test cases with proper setup and teardown
Clear test descriptions and naming conventions
Modular helper methods for common assertions
Comprehensive edge case coverage
Clean separation of concerns in test organization

thoughtbot/paperclip

spec/paperclip/has_attached_file_spec.rb

            
require 'spec_helper'

describe Paperclip::HasAttachedFile do
  context '#define_on' do
    it 'defines a setter on the class object' do
      assert_adding_attachment('avatar').defines_method('avatar=')
    end

    it 'defines a getter on the class object' do
      assert_adding_attachment('avatar').defines_method('avatar')
    end

    it 'defines a query on the class object' do
      assert_adding_attachment('avatar').defines_method('avatar?')
    end

    it 'defines a method on the class to get all of its attachments' do
      assert_adding_attachment('avatar').defines_class_method('attachment_definitions')
    end

    it 'flushes errors as part of validations' do
      assert_adding_attachment('avatar').defines_validation
    end

    it 'registers the attachment with Paperclip::AttachmentRegistry' do
      assert_adding_attachment('avatar').registers_attachment
    end

    it 'defines an after_save callback' do
      assert_adding_attachment('avatar').defines_callback('after_save')
    end

    it 'defines a before_destroy callback' do
      assert_adding_attachment('avatar').defines_callback('before_destroy')
    end

    it 'defines an after_commit callback' do
      assert_adding_attachment('avatar').defines_callback('after_commit')
    end

    context 'when the class does not allow after_commit callbacks' do
      it 'defines an after_destroy callback' do
        assert_adding_attachment(
          'avatar',
          unstub_methods: [:after_commit]
        ).defines_callback('after_destroy')
      end
    end

    it 'defines the Paperclip-specific callbacks' do
      assert_adding_attachment('avatar').defines_callback('define_paperclip_callbacks')
    end

    it 'does not define a media_type check if told not to' do
      assert_adding_attachment('avatar').does_not_set_up_media_type_check_validation
    end

    it 'does define a media_type check if told to' do
      assert_adding_attachment('avatar').sets_up_media_type_check_validation
    end
  end

  private

  def assert_adding_attachment(attachment_name, options={})
    AttachmentAdder.new(attachment_name, options)
  end

  class AttachmentAdder
    include Mocha::API
    include RSpec::Matchers

    def initialize(attachment_name, options = {})
      @attachment_name = attachment_name
      @stubbed_class = stub_class
      if options.present?
        options[:unstub_methods].each do |method|
          @stubbed_class.unstub(method)
        end
      end
    end

    def defines_method(method_name)
      a_class = @stubbed_class

      Paperclip::HasAttachedFile.define_on(a_class, @attachment_name, {})

      expect(a_class).to have_received(:define_method).with(method_name)
    end

    def defines_class_method(method_name)
      a_class = @stubbed_class
      a_class.class.stubs(:define_method)

      Paperclip::HasAttachedFile.define_on(a_class, @attachment_name, {})

      expect(a_class).to have_received(:extend).with(Paperclip::HasAttachedFile::ClassMethods)
    end

    def defines_validation
      a_class = @stubbed_class

      Paperclip::HasAttachedFile.define_on(a_class, @attachment_name, {})

      expect(a_class).to have_received(:validates_each).with(@attachment_name)
    end

    def registers_attachment
      a_class = @stubbed_class
      Paperclip::AttachmentRegistry.stubs(:register)

      Paperclip::HasAttachedFile.define_on(a_class, @attachment_name, {size: 1})

      expect(Paperclip::AttachmentRegistry).to have_received(:register).with(a_class, @attachment_name, {size: 1})
    end

    def defines_callback(callback_name)
      a_class = @stubbed_class

      Paperclip::HasAttachedFile.define_on(a_class, @attachment_name, {})

      expect(a_class).to have_received(callback_name.to_sym)
    end

    def does_not_set_up_media_type_check_validation
      a_class = stub_class

      Paperclip::HasAttachedFile.define_on(a_class, @attachment_name, { validate_media_type: false })

      expect(a_class).to have_received(:validates_media_type_spoof_detection).never
    end

    def sets_up_media_type_check_validation
      a_class = stub_class

      Paperclip::HasAttachedFile.define_on(a_class, @attachment_name, { validate_media_type: true })

      expect(a_class).to have_received(:validates_media_type_spoof_detection)
    end

    private

    def stub_class
      stub('class',
           validates_each: nil,
           define_method: nil,
           after_save: nil,
           before_destroy: nil,
           after_commit: nil,
           after_destroy: nil,
           define_paperclip_callbacks: nil,
           extend: nil,
           name: 'Billy',
           validates_media_type_spoof_detection: nil
          )
    end
  end
end