nextcloud/tests/acceptance/features/core/ElementWrapper.php

300 lines
10 KiB
PHP

<?php
/**
*
* @copyright Copyright (c) 2017, Daniel Calviño Sánchez (danxuliu@gmail.com)
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
/**
* Wrapper to automatically handle failed commands on Mink elements.
*
* Commands executed on Mink elements may fail for several reasons. The
* ElementWrapper frees the caller of the commands from handling the most common
* reasons of failure.
*
* StaleElementReference exceptions are thrown when the command is executed on
* an element that is no longer attached to the DOM. This can happen even in
* a chained call like "$actor->find($locator)->click()"; in the milliseconds
* between finding the element and clicking it the element could have been
* removed from the page (for example, if a previous interaction with the page
* started an asynchronous update of the DOM). Every command executed through
* the ElementWrapper is guarded against StaleElementReference exceptions; if
* the element is stale it is found again using the same parameters to find it
* in the first place.
*
* NoSuchElement exceptions are sometimes thrown instead of
* StaleElementReference exceptions. This can happen when the Selenium2 driver
* for Mink performs an action on an element through the WebDriver session
* instead of directly through the WebDriver element. In that case, if the
* element with the given ID does not exist, a NoSuchElement exception would be
* thrown instead of a StaleElementReference exception, so those cases are
* handled like StaleElementReference exceptions.
*
* ElementNotVisible exceptions are thrown when the command requires the element
* to be visible but the element is not. Finding an element only guarantees that
* (at that time) the element is attached to the DOM, but it does not provide
* any guarantee regarding its visibility. Due to that, a call like
* "$actor->find($locator)->click()" can fail if the element was hidden and
* meant to be made visible by a previous interaction with the page, but that
* interaction triggered an asynchronous update that was not finished when the
* click command is executed. All commands executed through the ElementWrapper
* that require the element to be visible are guarded against ElementNotVisible
* exceptions; if the element is not visible it is waited for it to be visible
* up to the timeout set to find it.
*
* MoveTargetOutOfBounds exceptions are sometimes thrown instead of
* ElementNotVisible exceptions. This can happen when the Selenium2 driver for
* Mink moves the cursor on an element using the "moveto" method of the
* WebDriver session, for example, before clicking on an element. In that case,
* if the element is not visible, "moveto" would throw a MoveTargetOutOfBounds
* exception instead of an ElementNotVisible exception, so those cases are
* handled like ElementNotVisible exceptions.
*
* Despite the automatic handling it is possible for the commands to throw those
* exceptions when they are executed again; this class does not handle cases
* like an element becoming stale several times in a row (uncommon) or an
* element not becoming visible before the timeout expires (which would mean
* that the timeout is too short or that the test has to, indeed, fail). In a
* similar way, MoveTargetOutOfBounds exceptions would be thrown again if
* originally they were thrown because the element was visible but "out of
* reach".
*
* If needed, automatically handling failed commands can be disabled calling
* "doNotHandleFailedCommands()"; as it returns the ElementWrapper it can be
* chained with the command to execute (but note that automatically handling
* failed commands will still be disabled if further commands are executed on
* the ElementWrapper).
*/
class ElementWrapper {
/**
* @var ElementFinder
*/
private $elementFinder;
/**
* @var \Behat\Mink\Element\Element
*/
private $element;
/**
* @param boolean
*/
private $handleFailedCommands;
/**
* Creates a new ElementWrapper.
*
* The wrapped element is found in the constructor itself using the
* ElementFinder.
*
* @param ElementFinder $elementFinder the command object to find the
* wrapped element.
* @throws NoSuchElementException if the element, or its ancestor, can not
* be found.
*/
public function __construct(ElementFinder $elementFinder) {
$this->elementFinder = $elementFinder;
$this->element = $elementFinder->find();
$this->handleFailedCommands = true;
}
/**
* Returns the raw Mink element.
*
* @return \Behat\Mink\Element\Element the wrapped element.
*/
public function getWrappedElement() {
return $this->element;
}
/**
* Prevents the automatic handling of failed commands.
*
* @return ElementWrapper this ElementWrapper.
*/
public function doNotHandleFailedCommands() {
$this->handleFailedCommands = false;
return $this;
}
/**
* Returns whether the wrapped element is visible or not.
*
* @return bool true if the wrapped element is visible, false otherwise.
*/
public function isVisible() {
$commandCallback = function() {
return $this->element->isVisible();
};
return $this->executeCommand($commandCallback, "visibility could not be got");
}
/**
* Returns the text of the wrapped element.
*
* If the wrapped element is not visible the returned text is an empty
* string.
*
* @return string the text of the wrapped element, or an empty string if it
* is not visible.
*/
public function getText() {
$commandCallback = function() {
return $this->element->getText();
};
return $this->executeCommand($commandCallback, "text could not be got");
}
/**
* Returns the value of the wrapped element.
*
* The value can be got even if the wrapped element is not visible.
*
* @return string the value of the wrapped element.
*/
public function getValue() {
$commandCallback = function() {
return $this->element->getValue();
};
return $this->executeCommand($commandCallback, "value could not be got");
}
/**
* Sets the given value on the wrapped element.
*
* If automatically waits for the wrapped element to be visible (up to the
* timeout set when finding it).
*
* @param string $value the value to set.
*/
public function setValue($value) {
$commandCallback = function() use ($value) {
$this->element->setValue($value);
};
$this->executeCommandOnVisibleElement($commandCallback, "value could not be set");
}
/**
* Clicks on the wrapped element.
*
* If automatically waits for the wrapped element to be visible (up to the
* timeout set when finding it).
*/
public function click() {
$commandCallback = function() {
$this->element->click();
};
$this->executeCommandOnVisibleElement($commandCallback, "could not be clicked");
}
/**
* Executes the given command.
*
* If a StaleElementReference or a NoSuchElement exception is thrown the
* wrapped element is found again and, then, the command is executed again.
*
* @param \Closure $commandCallback the command to execute.
* @param string $errorMessage an error message that describes the failed
* command (appended to the description of the element).
*/
private function executeCommand(\Closure $commandCallback, $errorMessage) {
if (!$this->handleFailedCommands) {
return $commandCallback();
}
try {
return $commandCallback();
} catch (\WebDriver\Exception\StaleElementReference $exception) {
$this->printFailedCommandMessage($exception, $errorMessage);
} catch (\WebDriver\Exception\NoSuchElement $exception) {
$this->printFailedCommandMessage($exception, $errorMessage);
}
$this->element = $this->elementFinder->find();
return $commandCallback();
}
/**
* Executes the given command on a visible element.
*
* If a StaleElementReference or a NoSuchElement exception is thrown the
* wrapped element is found again and, then, the command is executed again.
* If an ElementNotVisible or a MoveTargetOutOfBounds exception is thrown it
* is waited for the wrapped element to be visible and, then, the command is
* executed again.
*
* @param \Closure $commandCallback the command to execute.
* @param string $errorMessage an error message that describes the failed
* command (appended to the description of the element).
*/
private function executeCommandOnVisibleElement(\Closure $commandCallback, $errorMessage) {
if (!$this->handleFailedCommands) {
return $commandCallback();
}
try {
return $this->executeCommand($commandCallback, $errorMessage);
} catch (\WebDriver\Exception\ElementNotVisible $exception) {
$this->printFailedCommandMessage($exception, $errorMessage);
} catch (\WebDriver\Exception\MoveTargetOutOfBounds $exception) {
$this->printFailedCommandMessage($exception, $errorMessage);
}
$this->waitForElementToBeVisible();
return $commandCallback();
}
/**
* Prints information about the failed command.
*
* @param \Exception exception the exception thrown by the command.
* @param string $errorMessage an error message that describes the failed
* command (appended to the description of the locator of the element).
*/
private function printFailedCommandMessage(\Exception $exception, $errorMessage) {
echo $this->elementFinder->getDescription() . " " . $errorMessage . "\n";
echo "Exception message: " . $exception->getMessage() . "\n";
echo "Trying again\n";
}
/**
* Waits for the wrapped element to be visible.
*
* This method waits up to the timeout used when finding the wrapped
* element; therefore, it may return when the element is still not visible.
*
* @return boolean true if the element is visible after the wait, false
* otherwise.
*/
private function waitForElementToBeVisible() {
$isVisibleCallback = function() {
return $this->isVisible();
};
$timeout = $this->elementFinder->getTimeout();
$timeoutStep = $this->elementFinder->getTimeoutStep();
return Utils::waitFor($isVisibleCallback, $timeout, $timeoutStep);
}
}