using NATS.Server.TestUtilities; namespace NATS.Server.JetStream.Tests; public class JetStreamExpectedHeaderTests { [Fact] public async Task Expected_last_sequence_mismatch_returns_error() { await using var fx = await JetStreamApiFixture.StartWithStreamAsync("ORDERS", "orders.*"); _ = await fx.PublishAndGetAckAsync("orders.created", "1"); var ack = await fx.PublishWithExpectedLastSeqAsync("orders.created", "2", expectedLastSeq: 999); ack.ErrorCode.ShouldBe(10071); } }