Implementation:Teamcapybara Capybara Node Matchers Assert Selector

Knowledge Sources	Capybara
Domains	Testing, Assertions
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tools for asserting element presence, count, and text content provided by Capybara::Node::Matchers.

Description

Node::Matchers#assert_selector constructs a SelectorQuery, resolves it within synchronize, and raises Capybara::ExpectationNotMet if the result doesn't match count expectations. #has_selector? wraps this in make_predicate which catches ExpectationNotMet and returns Boolean.

Node::Matchers#assert_text verifies text content using TextQuery, with support for exact matching, normalization, and count expectations. #has_text? (aliased as has_content?) is the predicate form.

Usage

Use with RSpec matchers: expect(page).to have_selector(...) or call directly: page.assert_selector(...).

Code Reference

Source Location

Repository: capybara
File: lib/capybara/node/matchers.rb
Lines: L38-40 (has_selector?), L109-115 (assert_selector), L700-706 (assert_text), L738-741 (has_text?/has_content?)

Signature

def assert_selector(*args, &optional_filter_block)
  # @param args [Symbol, String, Hash] Selector args + options
  # @return [true]
  # @raise [Capybara::ExpectationNotMet]
end

def has_selector?(*args, **options, &optional_filter_block)
  # @return [Boolean]
end

def assert_text(type_or_text, *args, **opts)
  # @param type_or_text [:all, :visible, String, Regexp]
  # @return [true]
  # @raise [Capybara::ExpectationNotMet]
end

def has_text?(*args, **options)
  # @return [Boolean]
end
# alias: has_content?

Import

require 'capybara'
# Available on page, any Node::Base, and via RSpec matchers

I/O Contract

Inputs

Name	Type	Required	Description
selector args	Symbol, String	Yes	Selector type and locator
text	String/Regexp	No	Text content to verify
count	Integer	No	Exact expected count
minimum	Integer	No	Minimum expected count
maximum	Integer	No	Maximum expected count
between	Range	No	Range of expected counts
exact_text	Boolean/String	No	Require exact text match
wait	Numeric	No	Override default wait time

Outputs

Name	Type	Description
assert_*	true	Returns true on success, raises on failure
has_*?	Boolean	Returns true/false

Usage Examples

Selector Assertions

# With RSpec
expect(page).to have_selector('table tr', count: 5)
expect(page).to have_selector(:button, 'Submit')
expect(page).to have_no_selector('.error')

# Direct assertion
page.assert_selector('#content', visible: true)
page.assert_no_selector('.loading-spinner', wait: 10)

Text Assertions

expect(page).to have_text('Welcome, Alice')
expect(page).to have_content(/order #\d+/i)
expect(page).to have_no_text('Error')

# With exact matching
expect(page).to have_text('Total: $99.99', exact: true)

Related Pages

Implements Principle

Principle:Teamcapybara_Capybara_Element_Assertion

Uses Heuristic

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Implementation

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