fix(mtconnect): share MTConnectError text extraction; pin hollow-error refusal

2026-08-05 06:23:08 -04:00
parent 9f17d7efa2
commit 3b8b5a77e1
3 changed files with 93 additions and 21 deletions
@@ -212,6 +212,55 @@ public sealed class MTConnectAgentClientWriteTests
        outcome.AgentError.ShouldContain("Cannot find device data item: nosuchitem");
    }

+    /// <summary>
+    ///     An <c>MTConnectError</c> document carrying no readable <c>&lt;Error&gt;</c> detail is
+    ///     still a refusal. The Agent said no; that it said so unhelpfully changes nothing. The trap
+    ///     this pins is that the natural implementation — "return the joined error text, or null if
+    ///     there is none" — hands back the same <c>null</c> that means "this body was not an error
+    ///     document at all", silently converting the refusal into an acceptance.
+    /// </summary>
+    [Fact]
+    public async Task An_error_document_with_no_readable_detail_is_still_a_refusal()
+    {
+        const string HollowError =
+            """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <MTConnectError xmlns="urn:mtconnect.org:MTConnectError:1.3">
+              <Header creationTime="2026-08-05T12:00:00Z" sender="stub-agent" instanceId="1" version="1.3.0.12" bufferSize="1"/>
+              <Errors/>
+            </MTConnectError>
+            """;
+
+        using var client = new MTConnectAgentClient(
+            Options(), new StubHandler((_, _) => Task.FromResult(XmlOk(HollowError))));
+
+        var outcome = await client.WriteObservationAsync("StubDevice", "dev1_msg", "hi", CancellationToken.None);
+
+        outcome.Accepted.ShouldBeFalse();
+        outcome.AgentError.ShouldNotBeNullOrWhiteSpace();
+    }
+
+    /// <summary>The same, for an <c>&lt;Error&gt;</c> element that is present but blank.</summary>
+    [Fact]
+    public async Task An_error_document_whose_error_element_is_blank_is_still_a_refusal()
+    {
+        const string BlankError =
+            """
+            <?xml version="1.0" encoding="UTF-8"?>
+            <MTConnectError xmlns="urn:mtconnect.org:MTConnectError:1.3">
+              <Errors><Error>   </Error></Errors>
+            </MTConnectError>
+            """;
+
+        using var client = new MTConnectAgentClient(
+            Options(), new StubHandler((_, _) => Task.FromResult(XmlOk(BlankError))));
+
+        var outcome = await client.WriteObservationAsync("StubDevice", "dev1_msg", "hi", CancellationToken.None);
+
+        outcome.Accepted.ShouldBeFalse();
+        outcome.AgentError.ShouldNotBeNullOrWhiteSpace();
+    }
+
    [Fact]
    public async Task A_non_success_status_is_a_refusal_naming_the_status()
    {