Module: Testivai::Settle

Defined in:
lib/testivai/settle.rb

Overview

Page-settled probe: "has this page stopped changing?"

settle.js is GENERATED from packages/witness/src/capture/settle.ts, so every language polls the identical predicate.

Deliberately NOT network idle. Playwright's own docs mark that DISCOURAGED for testing, and it is the wrong signal for a visual snapshot anyway — a page with analytics beacons never goes quiet, while a network-idle page can still be animating. What matters is whether the rendered page settled.

Constant Summary collapse

DEFAULT_QUIET_MS = 
150
DEFAULT_TIMEOUT = 
5.0
ASSET = 
Pathname.new(__dir__).join("settle.js")
STOP_JS = 
<<~JS
  try { var s = window.__testivaiSettleState;
    if (s && s.observer && s.observer.disconnect) s.observer.disconnect(); } catch (e) {}
  try { delete window.__testivaiSettleState; } catch (e) {}
JS

Class Method Summary collapse

Class Method Details

.expression(quiet_ms = DEFAULT_QUIET_MS) ⇒ Object 



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# File 'lib/testivai/settle.rb', line 39

def expression(quiet_ms = DEFAULT_QUIET_MS)
  "return (#{source})(document, window, #{quiet_ms.to_i});"
end

.source ⇒ Object 



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# File 'lib/testivai/settle.rb', line 27

def source
  @source ||= begin
    # Explicit UTF-8: the generated asset is non-ASCII and Pathname#read
    # would otherwise use the default external encoding.
    raw = ASSET.read(encoding: "UTF-8")
    start = raw.index("function settleProbe")
    raise "settle.js is malformed: settleProbe not found" if start.nil?

    raw[start..].strip
  end
end

.stop(browser) ⇒ Object

Detach the observer so it does not linger on the page under test.



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# File 'lib/testivai/settle.rb', line 67

def stop(browser)
  browser.execute_script(STOP_JS)
rescue StandardError # rubocop:disable Lint/SuppressedException
end

.wait_for(browser, quiet_ms: DEFAULT_QUIET_MS, timeout: DEFAULT_TIMEOUT) ⇒ Object

Poll until settled or the deadline passes. Always bounded: a page that never settles yields a capture, not a hang. A browser that cannot evaluate the probe returns something unusable, so we proceed at once rather than paying the whole timeout on every capture.



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# File 'lib/testivai/settle.rb', line 47

def wait_for(browser, quiet_ms: DEFAULT_QUIET_MS, timeout: DEFAULT_TIMEOUT)
  expr = expression(quiet_ms)
  deadline = Time.now + timeout
  loop do
    state = begin
      browser.execute_script(expr)
    rescue StandardError
      return
    end
    return unless state.is_a?(Hash)

    settled = state["settled"]
    return unless [true, false].include?(settled)
    return if settled || Time.now >= deadline

    sleep 0.05
  end
end