test(batch7): implement t3 cross-cutting mapped tests

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/JwtProcessorTests.cs

@@ -1121,6 +1121,43 @@ public sealed class JwtProcessorTests
         "TestJWTAccountNATSResolverWrongCreds".ShouldNotBeNullOrWhiteSpace();
     }
 
+    [Fact] // T:1893
+    public void DefaultSentinelUser_ShouldSucceed()
+    {
+        var options = new ServerOptions();
+        var errors = new List<Exception>();
+        var warnings = new List<Exception>();
+
+        options.ProcessConfigFileLine("default_sentinel", "bearer.default.sentinel", errors, warnings);
+        errors.ShouldBeEmpty();
+        warnings.ShouldBeEmpty();
+        options.DefaultSentinel.ShouldBe("bearer.default.sentinel");
+
+        options.ProcessConfigFileLine("default_sentinel", 123L, errors, warnings);
+        errors.Count.ShouldBe(1);
+        errors[0].Message.ShouldContain("default_sentinel must be a string");
+
+        var (server, createError) = NatsServer.NewServer(new ServerOptions
+        {
+            NoLog = true,
+            NoSigs = true,
+        });
+        createError.ShouldBeNull();
+        server.ShouldNotBeNull();
+
+        try
+        {
+            var reloadOption = new DefaultSentinelReloadOption("updated.sentinel");
+
+            reloadOption.IsAuthChange().ShouldBeFalse();
+            Should.NotThrow(() => reloadOption.Apply(server!));
+        }
+        finally
+        {
+            server!.Shutdown();
+        }
+    }
+
     [Fact] // T:1895
     public void JWTJetStreamClientsExcludedForMaxConnsUpdate_ShouldSucceed()
     {