public function testUpsert()
{
$e = $this->prophesize(Entity::class);
$this->operation->mutation(Argument::exact('upsert'), Argument::type(Entity::class), Argument::exact(Entity::class, null))->shouldBeCalled()->willReturn(null);
$this->operation->commit()->shouldNotBeCalled();
$this->transaction->setOperation($this->operation->reveal());
$this->transaction->upsert($e->reveal());
}