test(batch26): port cross-module websocket-dependent tests

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JetStreamFileStoreTests.Impltests.cs

@@ -3372,4 +3372,68 @@ public sealed partial class JetStreamFileStoreTests
             Directory.Delete(root, recursive: true);
         }
     }
+
+    [Fact] // T:409
+    public void FileStoreCompactReclaimHeadSpace_ShouldSucceed()
+    {
+        WithStore((fs, root) =>
+        {
+            for (var i = 0; i < 120; i++)
+                fs.StoreMsg("cmp.a", null, new byte[512], 0);
+
+            fs.Compact(80).Error.ShouldBeNull();
+            var state = fs.State();
+            state.FirstSeq.ShouldBeGreaterThanOrEqualTo(80UL);
+            state.Msgs.ShouldBeLessThan(120UL);
+        }, cfg: DefaultStreamConfig(subjects: ["cmp.*"]), fcfg: new FileStoreConfig { BlockSize = 4096 });
+    }
+
+    [Fact] // T:465
+    public void FileStoreTrackSubjLenForPSIM_ShouldSucceed()
+    {
+        WithStore((fs, _) =>
+        {
+            for (var i = 0; i < 40; i++)
+            {
+                fs.StoreMsg($"psim.{i % 4}", null, "x"u8.ToArray(), 0);
+                fs.StoreMsg($"psim.long.subject.{i % 3}", null, "y"u8.ToArray(), 0);
+            }
+
+            var totals = fs.SubjectsTotals("psim.>");
+            totals.Count.ShouldBe(7);
+            totals.Keys.ShouldContain("psim.0");
+            totals.Keys.ShouldContain("psim.long.subject.0");
+            totals["psim.long.subject.0"].ShouldBeGreaterThan(0UL);
+        }, cfg: DefaultStreamConfig(subjects: ["psim.>"]));
+    }
+
+    [Fact] // T:466
+    public void FileStoreLargeFullStatePSIM_ShouldSucceed()
+    {
+        var root = NewRoot();
+        Directory.CreateDirectory(root);
+
+        try
+        {
+            var fs = JetStreamFileStore.NewFileStore(
+                new FileStoreConfig { StoreDir = root, BlockSize = 8192 },
+                DefaultStreamConfig(subjects: ["large.>"]));
+
+            for (var i = 0; i < 300; i++)
+                fs.StoreMsg($"large.{i % 25}", null, new byte[64], 0);
+
+            fs.State().Msgs.ShouldBeGreaterThan(0UL);
+            InvokePrivate<Exception?>(fs, "ForceWriteFullState").ShouldBeNull();
+
+            var stateFile = Path.Combine(root, FileStoreDefaults.MsgDir, FileStoreDefaults.StreamStateFile);
+            File.Exists(stateFile).ShouldBeTrue();
+            new FileInfo(stateFile).Length.ShouldBeGreaterThan(0L);
+            fs.Stop();
+        }
+        finally
+        {
+            if (Directory.Exists(root))
+                Directory.Delete(root, recursive: true);
+        }
+    }
 }