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Testing Adapter Registry Implementation in Paperclip

This test suite validates the functionality of Paperclip’s AttachmentRegistry and AdapterRegistry classes, focusing on adapter registration and lookup capabilities. The tests ensure proper handling of adapter registration and verification mechanisms within the Paperclip gem.

Test Coverage Overview

The test suite provides comprehensive coverage of the Paperclip adapter registry system, focusing on two main contexts: adapter lookup and registration verification.

Tests adapter retrieval functionality using the ‘for’ method
Validates adapter registration status checks
Covers both positive and negative test cases
Ensures proper initialization of adapters with targets

Implementation Analysis

The implementation uses RSpec’s context-based structure to organize related test cases logically. The testing approach employs before blocks for setup and uses mock adapter classes to validate registry behavior.

Key patterns include:

Isolated test contexts with independent setup
Mock adapter class implementation
Symbol-based target matching
Boolean assertion testing

Technical Details

Testing infrastructure includes:

RSpec as the testing framework
Custom AdapterTest class for mocking
Paperclip::AdapterRegistry implementation
Symbol-based type checking
Standard assertion methods

Best Practices Demonstrated

The test suite demonstrates several testing best practices in Ruby and RSpec.

Clear context separation and organization
Proper test setup isolation
Consistent naming conventions
Focused test cases with single assertions
Appropriate use of setup blocks
Both positive and negative test scenarios

thoughtbot/paperclip

spec/paperclip/io_adapters/registry_spec.rb

            
require 'spec_helper'

describe Paperclip::AttachmentRegistry do
  context "for" do
    before do
      class AdapterTest
        def initialize(_target, _ = {}); end
      end
      @subject = Paperclip::AdapterRegistry.new
      @subject.register(AdapterTest){|t| Symbol === t }
    end

    it "returns the class registered for the adapted type" do
      assert_equal AdapterTest, @subject.for(:target).class
    end
  end

  context "registered?" do
    before do
      class AdapterTest
        def initialize(_target, _ = {}); end
      end
      @subject = Paperclip::AdapterRegistry.new
      @subject.register(AdapterTest){|t| Symbol === t }
    end

    it "returns true when the class of this adapter has been registered" do
      assert @subject.registered?(AdapterTest.new(:target))
    end

    it "returns false when the adapter has not been registered" do
      assert ! @subject.registered?(Object)
    end
  end
end