Use the SpinCapableTrait¶

In Akeneo PIM we use spin as a Trait. To be able to use the spin method you only have to add the Trait in your decorator or your context as follows:

use Context\Spin\SpinCapableTrait;
use Pim\Behat\Decorator\ElementDecorator;

MyClassDecorator extends ElementDecorator {
    use SpinCapableTrait;
}

Spin Signature¶

In the method signature you can see two arguments.

// Context\Spin\SpinCapableTrait

public function spin($callable, $message) {}

The first one is a callable function. This function is where you search for your Element. If this callable returns false, null or throws an exception, the spin will retry every second the callable function until it returns a value or when the loop limit is reached.

The second one is the message that will be written in the console in case the loop limit is reached.

Example¶

Let’s see an example from the PermissionDecorator:

/**
 * @param string $group
 *
 * @return NodeElement
 */
public function findGroup($group)
{
    return $this->spin(function () use ($group) {
        return $this->find('css', sprintf('.tab-groups .tab:contains("%s")', $group));
    }, sprintf('Group "%s" not found.', $group));
}

Here we want to find an Element which contains the text $group. Searching for this Element in the page without spinning may not work as the loading of the page might not be complete. Waiting for the page to be completely loaded can lead to a significant time waiting, all the while knowing we can never be certain when this event will actually occur. Thanks to the spin, we just have to wait for a specific Element to appear. That’s why we never use the wait method from Behat.

Inform That Spin Failed¶

There are two ways to inform the developer the callable function has failed. The first one is to fill the second argument of the spin $message which was previously mentioned. The second one is to throw a SpinException from the callable. If an exception is thrown from the spin, the result is that the spin will retry and the $message will be replaced by the SpinException message.