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Testing Factory Definition Loading Patterns in factory_bot

This test suite validates FactoryBot’s definition loading functionality, ensuring proper discovery and loading of factory definition files across different directory structures and naming patterns.

Test Coverage Overview

The test suite provides comprehensive coverage of FactoryBot’s definition loading capabilities.

Key areas tested include:

Basic factories.rb file loading
Loading from spec/test directories
Nested factory file structures
Multiple factory file handling
Alphabetical loading order verification

Implementation Analysis

The testing approach uses RSpec shared examples and custom matchers to validate factory definition loading behavior. The implementation leverages directory manipulation and file creation to test various scenarios, with careful cleanup through before/after hooks.

Key patterns include:

Dynamic file path generation
Temporary directory management
Mock expectations for load order
Custom matcher definition for load verification

Technical Details

Testing tools and configuration:

RSpec for test framework
FileUtils for directory manipulation
Custom matcher definition for load verification
Temporary directory setup and teardown
Mock expectations using allow/receive patterns

Best Practices Demonstrated

The test suite exemplifies several testing best practices, including isolation of test environments, proper cleanup of test artifacts, and comprehensive edge case coverage.

Notable practices:

Shared example usage for common behaviors
Proper test isolation through directory management
Comprehensive file structure testing
Clear test organization and naming

thoughtbot/factory_bot

spec/factory_bot/find_definitions_spec.rb

            
require "fileutils"

shared_examples_for "finds definitions" do
  before do
    allow(FactoryBot).to receive(:load)
    FactoryBot.find_definitions
  end

  subject { FactoryBot }
end

RSpec::Matchers.define :load_definitions_from do |file|
  match do |given|
    @has_received = have_received(:load).with(File.expand_path(file))
    @has_received.matches?(given)
  end

  description do
    "load definitions from #{file}"
  end

  failure_message do
    @has_received.failure_message
  end
end

describe "definition loading" do
  def self.in_directory_with_files(*files)
    before do
      @pwd = Dir.pwd
      @tmp_dir = File.join(File.dirname(__FILE__), "tmp")
      FileUtils.mkdir_p @tmp_dir
      Dir.chdir(@tmp_dir)

      files.each do |file|
        FileUtils.mkdir_p File.dirname(file)
        FileUtils.touch file
      end
    end

    after do
      Dir.chdir(@pwd)
      FileUtils.rm_rf(@tmp_dir)
    end
  end

  describe "with factories.rb" do
    in_directory_with_files "factories.rb"
    it_should_behave_like "finds definitions" do
      it { should load_definitions_from("factories.rb") }
    end
  end

  %w[spec test].each do |dir|
    describe "with a factories file under #{dir}" do
      in_directory_with_files File.join(dir, "factories.rb")
      it_should_behave_like "finds definitions" do
        it { should load_definitions_from("#{dir}/factories.rb") }
      end
    end

    describe "with a factories file under #{dir}/factories" do
      in_directory_with_files File.join(dir, "factories", "post_factory.rb")
      it_should_behave_like "finds definitions" do
        it { should load_definitions_from("#{dir}/factories/post_factory.rb") }
      end
    end

    describe "with several factories files under #{dir}/factories" do
      in_directory_with_files File.join(dir, "factories", "post_factory.rb"),
        File.join(dir, "factories", "person_factory.rb")
      it_should_behave_like "finds definitions" do
        it { should load_definitions_from("#{dir}/factories/post_factory.rb") }
        it { should load_definitions_from("#{dir}/factories/person_factory.rb") }
      end
    end

    describe "with several factories files under #{dir}/factories in non-alphabetical order" do
      in_directory_with_files File.join(dir, "factories", "b.rb"),
        File.join(dir, "factories", "a.rb")
      it "loads the files in the right order" do
        allow(FactoryBot).to receive(:load)
        wd = File.dirname(__FILE__)
        file_b = File.join(wd, "tmp", dir, "factories", "b.rb")
        file_a = File.join(wd, "tmp", dir, "factories", "a.rb")

        FactoryBot.find_definitions

        expect(FactoryBot).to have_received(:load).with(file_a).ordered
        expect(FactoryBot).to have_received(:load).with(file_b).ordered
      end
    end

    describe "with nested and unnested factories files under #{dir}" do
      in_directory_with_files File.join(dir, "factories.rb"),
        File.join(dir, "factories", "post_factory.rb"),
        File.join(dir, "factories", "person_factory.rb")
      it_should_behave_like "finds definitions" do
        it { should load_definitions_from("#{dir}/factories.rb") }
        it { should load_definitions_from("#{dir}/factories/post_factory.rb") }
        it { should load_definitions_from("#{dir}/factories/person_factory.rb") }
      end
    end

    describe "with deeply nested factory files under #{dir}" do
      in_directory_with_files File.join(dir, "factories", "subdirectory", "post_factory.rb"),
        File.join(dir, "factories", "subdirectory", "person_factory.rb")
      it_should_behave_like "finds definitions" do
        it { should load_definitions_from("#{dir}/factories/subdirectory/post_factory.rb") }
        it { should load_definitions_from("#{dir}/factories/subdirectory/person_factory.rb") }
      end
    end
  end
end