Class: Capybara::Screenshot::Diff::StableScreenshoter

Inherits:
Object
  • Object
show all
Defined in:
lib/capybara/screenshot/diff/stable_screenshoter.rb

Constant Summary collapse

STABILITY_OPTIONS = 
[:stability_time_limit, :wait]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(capture_options, comparison_options = nil) ⇒ StableScreenshoter

Returns a new instance of StableScreenshoter.



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# File 'lib/capybara/screenshot/diff/stable_screenshoter.rb', line 11

def initialize(capture_options, comparison_options = nil)
  @stability_time_limit, @wait = capture_options.fetch_values(:stability_time_limit, :wait)
  @comparison_options = comparison_options || Diff.default_options
  @screenshoter = Diff.screenshoter.new(capture_options.except(*STABILITY_OPTIONS), @comparison_options[:driver])
end

Instance Attribute Details

#stability_time_limit ⇒ Object (readonly)

Returns the value of attribute stability_time_limit.



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# File 'lib/capybara/screenshot/diff/stable_screenshoter.rb', line 9

def stability_time_limit
  @stability_time_limit
end

#wait ⇒ Object (readonly)

Returns the value of attribute wait.



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# File 'lib/capybara/screenshot/diff/stable_screenshoter.rb', line 9

def wait
  @wait
end

Instance Method Details

#take_comparison_screenshot(screenshot_path) ⇒ Object

Try to get screenshot from browser. On ‘stability_time_limit` it checks that page stop updating by comparison several screenshot attempts On reaching `wait` limit then it has been failed. On failing we annotate screenshot attempts to help to debug



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# File 'lib/capybara/screenshot/diff/stable_screenshoter.rb', line 20

def take_comparison_screenshot(screenshot_path)
  new_screenshot_path = take_stable_screenshot(screenshot_path)

  # We failed to get stable browser state! Generate difference between attempts to overview moving parts!
  unless new_screenshot_path
    # FIXME(uwe): Change to store the failure and only report if the test succeeds functionally.
    annotate_attempts_and_fail!(screenshot_path)
  end

  FileUtils.mv(new_screenshot_path, screenshot_path, force: true)
  Screenshoter.cleanup_attempts_screenshots(screenshot_path)
end

#take_stable_screenshot(screenshot_path) ⇒ Object 



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# File 'lib/capybara/screenshot/diff/stable_screenshoter.rb', line 33

def take_stable_screenshot(screenshot_path)
  # We try to compare first attempt with checkout version, in order to not run next screenshots
  attempt_path = nil
  screenshot_started_at = last_attempt_at = Time.now

  # Cleanup all previous attempts for sure
  Screenshoter.cleanup_attempts_screenshots(screenshot_path)

  0.step do |i|
    # Prevents redundant screenshots generations
    sleep(stability_time_limit) unless i == 0

    elapsed_time = last_attempt_at - screenshot_started_at

    prev_attempt_path = attempt_path
    attempt_path = Screenshoter.gen_next_attempt_path(screenshot_path, i)

    @screenshoter.take_screenshot(attempt_path)
    last_attempt_at = Time.now

    next unless prev_attempt_path
    stabilization_comparator = build_comparison_for(attempt_path, prev_attempt_path)

    # If previous screenshot is equal to the current, then we are good
    return attempt_path if prev_attempt_path && stabilization_comparator.quick_equal?

    # If timeout then we failed to generate valid screenshot
    return nil if timeout?(elapsed_time)
  end
end