feat(health): core review fixes (async writer, gRPC cancellation, validation, configurable retry-after)

ZB.MOM.WW.Health/tests/ZB.MOM.WW.Health.Tests/GrpcDependencyHealthCheckTests.cs

@@ -14,14 +14,15 @@ public sealed class GrpcDependencyHealthCheckTests
 {
     private static readonly GrpcChannel Channel = GrpcChannel.ForAddress("http://localhost");
 
-    private static async Task<HealthCheckResult> RunAsync(GrpcDependencyOptions options)
+    private static async Task<HealthCheckResult> RunAsync(
+        GrpcDependencyOptions options, CancellationToken cancellationToken = default)
     {
         var check = new GrpcDependencyHealthCheck(Channel, options);
         var context = new HealthCheckContext
         {
             Registration = new HealthCheckRegistration("grpc-dep", check, HealthStatus.Unhealthy, tags: null),
         };
-        return await check.CheckHealthAsync(context, CancellationToken.None);
+        return await check.CheckHealthAsync(context, cancellationToken);
     }
 
     [Fact]
@@ -69,4 +70,38 @@ public sealed class GrpcDependencyHealthCheckTests
         Assert.Equal(HealthStatus.Unhealthy, result.Status);
         Assert.Contains("mxaccessgw worker", result.Description);
     }
+
+    [Fact]
+    public async Task ProbeExceedsTimeout_Unhealthy()
+    {
+        var result = await RunAsync(new GrpcDependencyOptions
+        {
+            Timeout = TimeSpan.FromMilliseconds(50),
+            Probe = static async (_, ct) =>
+            {
+                await Task.Delay(Timeout.Infinite, ct);
+                return true;
+            },
+        });
+
+        Assert.Equal(HealthStatus.Unhealthy, result.Status);
+    }
+
+    [Fact]
+    public async Task ExternalCancellation_Throws()
+    {
+        using var cts = new CancellationTokenSource();
+        await cts.CancelAsync();
+
+        await Assert.ThrowsAnyAsync<OperationCanceledException>(() => RunAsync(
+            new GrpcDependencyOptions
+            {
+                Probe = static async (_, ct) =>
+                {
+                    await Task.Delay(Timeout.Infinite, ct);
+                    return true;
+                },
+            },
+            cts.Token));
+    }
 }