behat selenium wait for steps

gistfile1.php

class FeatureContext extends MinkContext {
	/**
	 * @Given /^I wait for css element "([^"]+)" to (appear|disappear)$/
	 */
	public function iWaitForCssElement($element, $appear)
	{
		$xpath = $this->getSession()->getSelectorsHandler()->selectorToXpath('css', $element);
		$this->waitForXpath($xpath, $appear == 'appear');
	}

	private function waitForXpath($xpath, $appear)
	{
		$this->waitFor(function($context) use ($xpath, $appear) {
			$visible = $context->getSession()->getDriver()->isVisible($xpath);
			return $appear ? $visible : !$visible;
		});
	}

	private function waitForXpathNode($xpath, $appear)
	{
		$this->waitFor(function($context) use ($xpath, $appear) {
			try {
				$nodes = $context->getSession()->getDriver()->find($xpath);
				if (count($nodes) > 0) {
					assertEquals(1, count($nodes), "more than one element matched '$xpath'");
					$visible = $nodes[0]->isVisible();
					return $appear ? $visible : !$visible;
				} else {
					return !$appear;
				}
			} catch (WebDriver\Exception $e) {
				if ($e->getCode() == WebDriver\Exception::NO_SUCH_ELEMENT) {
					return !$appear;
				}
				throw $e;
			}
		});
	}

	/**
	 * @Given /^I wait for text "([^"]+)" to (appear|disappear)$/
	 */
	public function iWaitForText($text, $appear)
	{
		$this->waitForXpathNode(".//*[contains(normalize-space(string(text())), \"$text\")]", $appear == 'appear');
	}
	
	private function waitFor($fn, $timeout = 5000)
	{
		$start = microtime(true);
		$end = $start + $timeout / 1000.0;
		while (microtime(true) < $end) {
			if ($fn($this)) {
				return;
			}
		}
		throw new \Exception("waitFor timed out");
	}
}