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Validating Session Configuration Thread Safety in teamcapybara/capybara

This test suite validates Capybara’s session configuration functionality, focusing on threadsafe behavior and session-specific settings. It ensures proper isolation of configuration options between different test sessions and verifies thread-safety mechanisms.

Test Coverage Overview

The test suite comprehensively covers Capybara’s session configuration capabilities.

Key areas tested include:

Default session options inheritance from global configuration
Session-specific configuration isolation
Threadsafe mode behavior and restrictions
Configuration block validation
Runtime configuration modification constraints

Implementation Analysis

The testing approach utilizes RSpec to validate session configuration behavior in both threadsafe and non-threadsafe modes.

Implementation patterns include:

Dynamic configuration verification using metaprogramming
Isolation testing through session-specific configurations
Error condition validation for invalid configurations
Runtime state verification

Technical Details

Testing infrastructure includes:

RSpec as the testing framework
Capybara’s rack_test driver
TestApp fixture application
Session configuration API
Thread safety mechanisms

Best Practices Demonstrated

The test suite exemplifies high-quality testing practices through comprehensive coverage of configuration scenarios.

Notable practices include:

Systematic validation of configuration inheritance
Explicit thread safety verification
Thorough error condition testing
Clear separation of global and session-specific concerns

teamcapybara/capybara

spec/per_session_config_spec.rb

            
# frozen_string_literal: true

require 'spec_helper'
require 'capybara/dsl'

RSpec.describe Capybara::SessionConfig do
  describe 'threadsafe' do
    it 'defaults to global session options' do
      Capybara.threadsafe = true
      session = Capybara::Session.new(:rack_test, TestApp)
      %i[default_host app_host always_include_port run_server
         default_selector default_max_wait_time ignore_hidden_elements
         automatic_reload match exact raise_server_errors visible_text_only
         automatic_label_click enable_aria_label save_path
         asset_host default_retry_interval].each do |m|
           expect(session.config.public_send(m)).to eq Capybara.public_send(m)
         end
    end

    it "doesn't change global session when changed" do
      Capybara.threadsafe = true
      host = 'http://my.example.com'
      session = Capybara::Session.new(:rack_test, TestApp) do |config|
        config.default_host = host
        config.automatic_label_click = !config.automatic_label_click
        config.server_errors << ArgumentError
      end
      expect(Capybara.default_host).not_to eq host
      expect(session.config.default_host).to eq host
      expect(Capybara.automatic_label_click).not_to eq session.config.automatic_label_click
      expect(Capybara.server_errors).not_to eq session.config.server_errors
    end

    it "doesn't allow session configuration block when false" do
      Capybara.threadsafe = false
      expect do
        Capybara::Session.new(:rack_test, TestApp) { |config| }
      end.to raise_error 'A configuration block is only accepted when Capybara.threadsafe == true'
    end

    it "doesn't allow session config when false" do
      Capybara.threadsafe = false
      session = Capybara::Session.new(:rack_test, TestApp)
      expect { session.config.default_selector = :title }.to raise_error(/Per session settings are only supported when Capybara.threadsafe == true/)
      expect do
        session.configure do |config|
          config.exact = true
        end
      end.to raise_error(/Session configuration is only supported when Capybara.threadsafe == true/)
    end

    it 'uses the config from the session' do
      Capybara.threadsafe = true
      session = Capybara::Session.new(:rack_test, TestApp) do |config|
        config.default_selector = :link
      end
      session.visit('/with_html')
      expect(session.find('foo').tag_name).to eq 'a'
    end

    it "won't change threadsafe once a session is created" do
      Capybara.threadsafe = true
      Capybara.threadsafe = false
      Capybara::Session.new(:rack_test, TestApp)
      expect { Capybara.threadsafe = true }.to raise_error(/Threadsafe setting cannot be changed once a session is created/)
    end
  end
end