public function testDelete()
{
$k = $this->prophesize(Key::class);
$this->operation->mutation(Argument::exact('delete'), Argument::type(Key::class), Argument::exact(Key::class, null))->shouldBeCalled()->willReturn(null);
$this->operation->commit()->shouldNotBeCalled();
$this->transaction->setOperation($this->operation->reveal());
$this->transaction->delete($k->reveal());
}