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Testing Registry Object Management in factory_bot

This test suite validates the functionality of FactoryBot’s Registry class, which manages object registration and retrieval in the factory_bot library. The tests ensure proper enumeration, registration, and lookup of objects with comprehensive error handling.

Test Coverage Overview

The test suite provides extensive coverage of the Registry class functionality:

Object registration and retrieval mechanisms
Enumerable interface implementation
Error handling for missing objects
Symbol and string key support
Duplicate object handling
Registry clearing capabilities

Implementation Analysis

The testing approach employs RSpec’s behavior-driven development patterns with extensive use of doubles for isolation. The implementation validates both standard and edge cases using RSpec’s expectation syntax and custom matchers for did_you_mean functionality.

Key patterns include object registration verification, enumeration testing, and error state validation.

Technical Details

Testing tools and configuration:

RSpec as the testing framework
Test doubles for dependency isolation
Custom matchers for error validation
Symbol and string key testing
Enumerable module integration testing

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Isolated test cases with clear arrangements
Comprehensive error scenario coverage
Consistent use of test doubles
Clear test descriptions
Proper separation of concerns
Thorough edge case handling

thoughtbot/factory_bot

spec/factory_bot/registry_spec.rb

            
describe FactoryBot::Registry do
  it "is an enumerable" do
    registry = FactoryBot::Registry.new("Great thing")

    expect(registry).to be_kind_of(Enumerable)
  end

  it "finds a registered object" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")
    registry.register(:object_name, registered_object)

    expect(registry.find(:object_name)).to eq registered_object
  end

  it "finds a registered object with square brackets" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")
    registry.register(:object_name, registered_object)

    expect(registry[:object_name]).to eq registered_object
  end

  it "raises when an object cannot be found" do
    registry = FactoryBot::Registry.new("Great thing")

    expect { registry.find(:object_name) }
      .to raise_error(KeyError, "Great thing not registered: \"object_name\"")
  end

  it "includes a did_you_mean message" do
    registry = FactoryBot::Registry.new(:registry)
    registered_object = double(:registered_object)
    registry.register(:factory_bot, registered_object)

    expect { registry.find(:factory_bit) }.to raise_did_you_mean_error
  end

  it "adds and returns the object registered" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")

    expect(registry.register(:object_name, registered_object)).to eq registered_object
  end

  it "knows that an object is registered by symbol" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")
    registry.register(:object_name, registered_object)

    expect(registry).to be_registered(:object_name)
  end

  it "knows that an object is registered by string" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")
    registry.register(:object_name, registered_object)

    expect(registry).to be_registered("object_name")
  end

  it "knows when an object is not registered" do
    registry = FactoryBot::Registry.new("Great thing")

    expect(registry).not_to be_registered("bogus")
  end

  it "iterates registered objects" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")
    second_registered_object = double("second registered object")
    registry.register(:first_object, registered_object)
    registry.register(:second_object, second_registered_object)

    expect(registry.to_a).to eq [registered_object, second_registered_object]
  end

  it "does not include duplicate objects with registered under different names" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")
    registry.register(:first_object, registered_object)
    registry.register(:second_object, registered_object)

    expect(registry.to_a).to eq [registered_object]
  end

  it "clears registered factories" do
    registry = FactoryBot::Registry.new("Great thing")
    registered_object = double("registered object")
    registry.register(:object_name, registered_object)
    registry.clear

    expect(registry.count).to be_zero
  end
end