public function testCommitWithMutation()
{
$this->connection->commit(Argument::that(function ($arg) {
if (count($arg['mutations']) !== 1) {
return false;
}
return true;
}))->shouldBeCalled()->willReturn(['foo']);
$this->operation->setConnection($this->connection->reveal());
$key = $this->prophesize(Key::class);
$e = new Entity($key->reveal());
$mutation = $this->operation->mutation('insert', $e, Entity::class, null);
$this->operation->commit([$mutation]);
}