merge: external-system retry policy end-to-end (register row 27) — MaxRetries/RetryDelay now travel artifact→gRPC→site schema→S&F enqueue, CLI --max-retries/--retry-delay-seconds, ArtifactDiff compares them

tests/ZB.MOM.WW.ScadaBridge.Transport.Tests/Import/ArtifactDiffTests.cs

@@ -9,6 +9,7 @@ using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Transport;
 using ZB.MOM.WW.ScadaBridge.Transport.Import;
 using ZB.MOM.WW.ScadaBridge.Transport.Serialization;
+using ZB.MOM.WW.ScadaBridge.Commons.Entities.ExternalSystems;
 
 namespace ZB.MOM.WW.ScadaBridge.Transport.Tests.Import;
 
@@ -105,6 +106,56 @@ public sealed class ArtifactDiffTests
         Assert.Null(item.FieldDiffJson);
     }
 
+    // ============ Deferred-work row 27: ES retry policy in the diff ============
+
+    /// <summary>
+    /// The bundle has always CARRIED the external-system retry policy and
+    /// <c>BundleImporter</c> has always APPLIED it, but <c>CompareExternalSystem</c> never
+    /// compared it — so an import that silently changed a system's retry budget previewed as
+    /// "Identical". Now that the policy actually reaches sites, an unreviewed change to it is a
+    /// live behaviour change, so it must show up in the preview.
+    /// </summary>
+    [Fact]
+    public void ExternalSystem_ChangedRetryPolicy_IsReported()
+    {
+        var existing = new ExternalSystemDefinition("Mes", "https://mes", "ApiKey")
+        {
+            MaxRetries = 3,
+            RetryDelay = TimeSpan.FromSeconds(5),
+        };
+        var incoming = new ExternalSystemDto("Mes", "https://mes", "ApiKey",
+            MaxRetries: 9, RetryDelay: TimeSpan.FromSeconds(45), Methods: [], Secrets: null);
+
+        var item = _diff.CompareExternalSystem(incoming, existing, []);
+
+        Assert.Equal(ConflictKind.Modified, item.Kind);
+
+        var maxRetries = ChangeFor(item, "MaxRetries");
+        Assert.Equal("3", maxRetries.GetProperty("oldValue").GetString());
+        Assert.Equal("9", maxRetries.GetProperty("newValue").GetString());
+
+        var retryDelay = ChangeFor(item, "RetryDelay");
+        Assert.Equal(TimeSpan.FromSeconds(5).ToString(), retryDelay.GetProperty("oldValue").GetString());
+        Assert.Equal(TimeSpan.FromSeconds(45).ToString(), retryDelay.GetProperty("newValue").GetString());
+    }
+
+    /// <summary>An unchanged retry policy must not manufacture a spurious diff row.</summary>
+    [Fact]
+    public void ExternalSystem_UnchangedRetryPolicy_IsIdentical()
+    {
+        var existing = new ExternalSystemDefinition("Mes", "https://mes", "ApiKey")
+        {
+            MaxRetries = 3,
+            RetryDelay = TimeSpan.FromSeconds(5),
+        };
+        var incoming = new ExternalSystemDto("Mes", "https://mes", "ApiKey",
+            MaxRetries: 3, RetryDelay: TimeSpan.FromSeconds(5), Methods: [], Secrets: null);
+
+        var item = _diff.CompareExternalSystem(incoming, existing, []);
+
+        Assert.Equal(ConflictKind.Identical, item.Kind);
+    }
+
     [Fact]
     public void ApiMethod_ModifiedScript_EmitsStructuredLineDiff()
     {