public function testSendToAllCallsFailureCallback()
{
$command = 'stats';
$connection1 = $this->getMockConnection('id-123');
$connection1->expects($this->any())->method($command)->will($this->throwException(new RuntimeException()));
$connection2 = $this->getMockConnection('id-456');
$connection2->expects($this->any())->method($command)->will($this->throwException(new RuntimeException()));
$failed = 0;
$onFailure = function () use(&$failed) {
$failed++;
};
$collection = new Collection([$connection1, $connection2]);
$collection->sendToAll($command, [], null, $onFailure);
$this->assertEquals(2, $failed);
}