Back to Repositories

Testing DOM Ancestor Detection Features in Capybara

This test suite validates the ancestor element detection functionality in Capybara, focusing on the #have_ancestor and #have_no_ancestor matchers. It ensures proper DOM traversal and relationship verification between elements in web pages during testing.

Test Coverage Overview

The test suite comprehensively covers ancestor element validation in Capybara with multiple scenarios:

Direct ancestor detection using CSS selectors
Multi-level ancestor validation
Multiple matching ancestors handling
Negative ancestor assertions
Count-based ancestor validations

Implementation Analysis

The implementation uses RSpec’s expectation syntax with Capybara’s custom matchers. The tests leverage CSS selectors for element location and employ both positive and negative assertions through have_ancestor and have_no_ancestor matchers. The implementation includes count validation methods like .once and .exactly(n).times.

Technical Details

Tools and configurations include:

RSpec testing framework
Capybara’s SpecHelper for test setup
CSS selector-based element location
Before hooks for test state initialization
Custom expectation matchers for ancestor validation

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Isolated test cases with clear assertions
Consistent setup using before blocks
Both positive and negative test scenarios
Edge case handling for multiple matches
Explicit count validation tests

teamcapybara/capybara

lib/capybara/spec/session/has_ancestor_spec.rb

            
# frozen_string_literal: true

Capybara::SpecHelper.spec '#have_ancestor' do
  before do
    @session.visit('/with_html')
  end

  it 'should assert an ancestor using the given locator' do
    el = @session.find(:css, '#ancestor1')
    expect(el).to have_ancestor(:css, '#ancestor2')
  end

  it 'should assert an ancestor even if not parent' do
    el = @session.find(:css, '#child')
    expect(el).to have_ancestor(:css, '#ancestor3')
  end

  it 'should not raise an error if there are multiple matches' do
    el = @session.find(:css, '#child')
    expect(el).to have_ancestor(:css, 'div')
  end

  it 'should allow counts to be specified' do
    el = @session.find(:css, '#child')

    expect do
      expect(el).to have_ancestor(:css, 'div').once
    end.to raise_error(RSpec::Expectations::ExpectationNotMetError)

    expect(el).to have_ancestor(:css, 'div').exactly(3).times
  end
end

Capybara::SpecHelper.spec '#have_no_ancestor' do
  before do
    @session.visit('/with_html')
  end

  it 'should assert no matching ancestor' do
    el = @session.find(:css, '#ancestor1')
    expect(el).to have_no_ancestor(:css, '#child')
    expect(el).to have_no_ancestor(:css, '#ancestor1_sibling')
    expect(el).not_to have_ancestor(:css, '#child')
    expect(el).not_to have_ancestor(:css, '#ancestor1_sibling')
  end
end