Expand XML docs across bridge and test code

tests/ZB.MOM.WW.LmxOpcUa.Tests/Domain/MxErrorCodesTests.cs

@@ -4,8 +4,16 @@ using ZB.MOM.WW.LmxOpcUa.Host.Domain;
 
 namespace ZB.MOM.WW.LmxOpcUa.Tests.Domain
 {
+    /// <summary>
+    /// Verifies the operator-facing error messages and quality mappings derived from MXAccess error codes.
+    /// </summary>
     public class MxErrorCodesTests
     {
+        /// <summary>
+        /// Confirms that known MXAccess error codes produce readable operator-facing descriptions.
+        /// </summary>
+        /// <param name="code">The MXAccess error code.</param>
+        /// <param name="expectedSubstring">A substring expected in the returned description.</param>
         [Theory]
         [InlineData(1008, "Invalid reference")]
         [InlineData(1012, "Wrong data type")]
@@ -18,6 +26,9 @@ namespace ZB.MOM.WW.LmxOpcUa.Tests.Domain
             MxErrorCodes.GetMessage(code).ShouldContain(expectedSubstring);
         }
 
+        /// <summary>
+        /// Confirms that unknown MXAccess error codes are reported as unknown while preserving the numeric code.
+        /// </summary>
         [Fact]
         public void GetMessage_UnknownCode_ReturnsUnknown()
         {
@@ -25,6 +36,11 @@ namespace ZB.MOM.WW.LmxOpcUa.Tests.Domain
             MxErrorCodes.GetMessage(9999).ShouldContain("9999");
         }
 
+        /// <summary>
+        /// Confirms that known MXAccess error codes map to the expected bridge quality values.
+        /// </summary>
+        /// <param name="code">The MXAccess error code.</param>
+        /// <param name="expected">The expected bridge quality value.</param>
         [Theory]
         [InlineData(1008, Quality.BadConfigError)]
         [InlineData(1012, Quality.BadConfigError)]
@@ -37,6 +53,9 @@ namespace ZB.MOM.WW.LmxOpcUa.Tests.Domain
             MxErrorCodes.MapToQuality(code).ShouldBe(expected);
         }
 
+        /// <summary>
+        /// Confirms that unknown MXAccess error codes map to the generic bad quality bucket.
+        /// </summary>
         [Fact]
         public void MapToQuality_UnknownCode_ReturnsBad()
         {