feat: add jetstream consumer api lifecycle

tests/NATS.Server.Tests/JetStreamApiFixture.cs

@@ -9,16 +9,19 @@ namespace NATS.Server.Tests;
 internal sealed class JetStreamApiFixture : IAsyncDisposable
 {
     private static readonly StreamManager SharedStreamManager = new();
-    private static readonly JetStreamApiRouter SharedRouter = new(SharedStreamManager);
+    private static readonly ConsumerManager SharedConsumerManager = new();
+    private static readonly JetStreamApiRouter SharedRouter = new(SharedStreamManager, SharedConsumerManager);
 
     private readonly StreamManager _streamManager;
+    private readonly ConsumerManager _consumerManager;
     private readonly JetStreamApiRouter _router;
     private readonly JetStreamPublisher _publisher;
 
     private JetStreamApiFixture()
     {
         _streamManager = new StreamManager();
-        _router = new JetStreamApiRouter(_streamManager);
+        _consumerManager = new ConsumerManager();
+        _router = new JetStreamApiRouter(_streamManager, _consumerManager);
         _publisher = new JetStreamPublisher(_streamManager);
     }
 
@@ -56,5 +59,17 @@ internal sealed class JetStreamApiFixture : IAsyncDisposable
         return _streamManager.GetStateAsync(streamName, default).AsTask();
     }
 
+    public Task<JetStreamApiResponse> CreateConsumerAsync(string stream, string durableName, string filterSubject)
+    {
+        var payload = $@"{{""durable_name"":""{durableName}"",""filter_subject"":""{filterSubject}""}}";
+        return RequestLocalAsync($"$JS.API.CONSUMER.CREATE.{stream}.{durableName}", payload);
+    }
+
+    public async Task<JetStreamConsumerInfo> GetConsumerInfoAsync(string stream, string durableName)
+    {
+        var response = await RequestLocalAsync($"$JS.API.CONSUMER.INFO.{stream}.{durableName}", "{}");
+        return response.ConsumerInfo ?? throw new InvalidOperationException("Consumer not found.");
+    }
+
     public ValueTask DisposeAsync() => ValueTask.CompletedTask;
 }

tests/NATS.Server.Tests/JetStreamConsumerApiTests.cs

@@ -0,0 +1,16 @@
+namespace NATS.Server.Tests;
+
+public class JetStreamConsumerApiTests
+{
+    [Fact]
+    public async Task Create_consumer_and_fetch_info_roundtrip()
+    {
+        await using var fixture = await JetStreamApiFixture.StartWithStreamAsync("ORDERS", "orders.*");
+
+        var create = await fixture.CreateConsumerAsync("ORDERS", "DUR", "orders.created");
+        create.Error.ShouldBeNull();
+
+        var info = await fixture.GetConsumerInfoAsync("ORDERS", "DUR");
+        info.Config.DurableName.ShouldBe("DUR");
+    }
+}