fix(inbound): type SITE_UNREACHABLE on AskTimeoutException at the router await instead of message-substring sniffing (plan R2-06 T5)

tests/ZB.MOM.WW.ScadaBridge.InboundAPI.Tests/InboundScriptExecutorTests.cs

@@ -98,19 +98,17 @@ public class InboundScriptExecutorTests
     }
 
     [Fact]
-    public async Task RoutedSiteUnreachable_Returns500WithSiteUnreachableCode()
+    public async Task RoutedAskTimeout_Returns500WithSiteUnreachableCode()
     {
-        // C3: a routed call whose site is unreachable must surface the machine-readable
-        // SITE_UNREACHABLE code (spec Component-InboundAPI failure body) rather than
-        // collapsing into a generic SCRIPT_ERROR.
+        // N3: unreachability is the Ask EXPIRING (site never answered) — typed as
+        // AskTimeoutException by the communication layer — not a substring in a
+        // failure message. Pre-fix this fell into the generic catch as SCRIPT_ERROR.
         var locator = Substitute.For<IInstanceLocator>();
         locator.GetSiteIdForInstanceAsync("X", Arg.Any<CancellationToken>()).Returns("SiteA");
         var router = Substitute.For<IInstanceRouter>();
         router.RouteToCallAsync("SiteA", Arg.Any<RouteToCallRequest>(), Arg.Any<CancellationToken>())
-            .Returns(ci => new RouteToCallResponse(
-                ((RouteToCallRequest)ci[1]).CorrelationId,
-                Success: false, ReturnValue: null, ErrorMessage: "Site unreachable",
-                DateTimeOffset.UtcNow));
+            .Returns(Task.FromException<RouteToCallResponse>(
+                new Akka.Actor.AskTimeoutException("Timeout after 00:00:30")));
         var route = new RouteHelper(locator, router);
 
         var method = new ApiMethod("routed", "return await Route.To(\"X\").Call(\"s\");")
@@ -123,6 +121,33 @@ public class InboundScriptExecutorTests
         Assert.Equal("SITE_UNREACHABLE", result.ErrorCode);
     }
 
+    [Fact]
+    public async Task SiteRespondedFailure_MessageMentioningUnreachable_IsScriptErrorNotSiteUnreachable()
+    {
+        // N3 anti-sniff: a site that RESPONDED with Success=false is reachable by
+        // definition — even when its error text happens to contain "unreachable".
+        // Pre-fix the substring sniff misclassified this as SITE_UNREACHABLE.
+        var locator = Substitute.For<IInstanceLocator>();
+        locator.GetSiteIdForInstanceAsync("X", Arg.Any<CancellationToken>()).Returns("SiteA");
+        var router = Substitute.For<IInstanceRouter>();
+        router.RouteToCallAsync("SiteA", Arg.Any<RouteToCallRequest>(), Arg.Any<CancellationToken>())
+            .Returns(ci => new RouteToCallResponse(
+                ((RouteToCallRequest)ci[1]).CorrelationId,
+                Success: false, ReturnValue: null,
+                ErrorMessage: "PLC device unreachable behind the site gateway",
+                DateTimeOffset.UtcNow));
+        var route = new RouteHelper(locator, router);
+
+        var method = new ApiMethod("routed2", "return await Route.To(\"X\").Call(\"s\");")
+        { Id = 8, TimeoutSeconds = 10 };
+
+        var result = await _executor.ExecuteAsync(
+            method, new Dictionary<string, object?>(), route, TimeSpan.FromSeconds(10));
+
+        Assert.False(result.Success);
+        Assert.Equal("SCRIPT_ERROR", result.ErrorCode);
+    }
+
     [Fact]
     public async Task HandlerTimesOut_ReturnsTimeoutError()
     {

tests/ZB.MOM.WW.ScadaBridge.InboundAPI.Tests/RouteHelperTests.cs

@@ -595,4 +595,30 @@ public class RouteHelperTests
         Assert.NotNull(captured);
         Assert.Equal(inboundExecutionId, captured!.ParentExecutionId);
     }
+
+    // --- N3: typed unreachability at the Ask boundary ---
+
+    [Fact]
+    public async Task Call_AskTimeout_ThrowsSiteUnreachableException()
+    {
+        SiteResolves("inst", "SiteA");
+        _router.RouteToCallAsync("SiteA", Arg.Any<RouteToCallRequest>(), Arg.Any<CancellationToken>())
+            .Returns(Task.FromException<RouteToCallResponse>(
+                new Akka.Actor.AskTimeoutException("Timeout after 00:00:30")));
+
+        await Assert.ThrowsAsync<SiteUnreachableException>(
+            () => CreateHelper().To("inst").Call("s"));
+    }
+
+    [Fact]
+    public async Task GetAttributes_AskTimeout_ThrowsSiteUnreachableException()
+    {
+        SiteResolves("inst", "SiteA");
+        _router.RouteToGetAttributesAsync("SiteA", Arg.Any<RouteToGetAttributesRequest>(), Arg.Any<CancellationToken>())
+            .Returns(Task.FromException<RouteToGetAttributesResponse>(
+                new Akka.Actor.AskTimeoutException("Timeout after 00:00:30")));
+
+        await Assert.ThrowsAsync<SiteUnreachableException>(
+            () => CreateHelper().To("inst").GetAttributes(new[] { "a" }));
+    }
 }