Enhance OptionObject and RowObject helpers with locking and unlocking…

.github/instructions/dotnet.instructions.md

@@ -57,6 +57,8 @@ To provide the broadest compatibility, core libraries target .NET Standard 2.0,
 ### Testing
 - Write unit tests for all public methods and critical logic
 - Use descriptive test names that explain what is being tested and expected outcome
+- Use helper test method naming pattern: `MethodName_Type_Scenario_ExpectedResult` (example: `SetLockedField_OptionObject2015_WithEmptyFieldNumber_ThrowsArgumentException`)
+- For OptionObject helper tests, keep one test file per type (`OptionObject`, `OptionObject2`, `OptionObject2015`) instead of combining all three in a single file
 - Follow the Arrange-Act-Assert (AAA) pattern in test methods
 - Test both success and failure scenarios
 - Aim for high code coverage on critical paths

dotnet/RarelySimple.AvatarScriptLink.Objects.Helpers.Tests/ArgumentGuardsTests.cs

@@ -0,0 +1,119 @@
+using System;
+using System.Collections.Generic;
+
+namespace RarelySimple.AvatarScriptLink.Objects.Helpers.Tests
+{
+    /// <summary>
+    /// Tests for internal ArgumentGuards validation helpers.
+    /// </summary>
+    [TestClass]
+    public class ArgumentGuardsTests
+    {
+        [TestMethod]
+        public void ValidateFieldNumber_ArgumentGuards_WithNullFieldNumber_ThrowsArgumentNullException()
+        {
+            var ex = Assert.ThrowsException<ArgumentNullException>(
+                () => ArgumentGuards.ValidateFieldNumber(null!, "fieldNumber"));
+
+            Assert.AreEqual("fieldNumber", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateFieldNumber_ArgumentGuards_WithEmptyFieldNumber_ThrowsArgumentException()
+        {
+            var ex = Assert.ThrowsException<ArgumentException>(
+                () => ArgumentGuards.ValidateFieldNumber(string.Empty, "fieldNumber"));
+
+            Assert.AreEqual("fieldNumber", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateFieldNumber_ArgumentGuards_WithValidFieldNumber_DoesNotThrow()
+        {
+            ArgumentGuards.ValidateFieldNumber("100", "fieldNumber");
+        }
+
+        [TestMethod]
+        public void ValidateAndNormalizeFieldNumbers_ArgumentGuards_WithNullFieldNumbers_ThrowsArgumentNullException()
+        {
+            var ex = Assert.ThrowsException<ArgumentNullException>(
+                () => ArgumentGuards.ValidateAndNormalizeFieldNumbers(null!, "fieldNumbers"));
+
+            Assert.AreEqual("fieldNumbers", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateAndNormalizeFieldNumbers_ArgumentGuards_WithEmptyFieldNumbers_ThrowsArgumentException()
+        {
+            var ex = Assert.ThrowsException<ArgumentException>(
+                () => ArgumentGuards.ValidateAndNormalizeFieldNumbers(new List<string>(), "fieldNumbers"));
+
+            Assert.AreEqual("fieldNumbers", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateAndNormalizeFieldNumbers_ArgumentGuards_WithOnlyEmptyValues_ThrowsArgumentException()
+        {
+            var ex = Assert.ThrowsException<ArgumentException>(
+                () => ArgumentGuards.ValidateAndNormalizeFieldNumbers(new List<string> { string.Empty, null!, string.Empty }, "fieldNumbers"));
+
+            Assert.AreEqual("fieldNumbers", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateAndNormalizeFieldNumbers_ArgumentGuards_WithDuplicatesAndEmptyValues_ReturnsDistinctNonEmptyValues()
+        {
+            var result = ArgumentGuards.ValidateAndNormalizeFieldNumbers(
+                new List<string> { "100", string.Empty, "100", "101", "101" },
+                "fieldNumbers");
+
+            CollectionAssert.AreEqual(new List<string> { "100", "101" }, result);
+        }
+
+        [TestMethod]
+        public void ValidateAndGetFieldNumbers_ArgumentGuards_WithNullFieldObjects_ThrowsArgumentNullException()
+        {
+            var ex = Assert.ThrowsException<ArgumentNullException>(
+                () => ArgumentGuards.ValidateAndGetFieldNumbers(null!, "fieldObjects"));
+
+            Assert.AreEqual("fieldObjects", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateAndGetFieldNumbers_ArgumentGuards_WithEmptyFieldObjects_ThrowsArgumentException()
+        {
+            var ex = Assert.ThrowsException<ArgumentException>(
+                () => ArgumentGuards.ValidateAndGetFieldNumbers(new List<FieldObject>(), "fieldObjects"));
+
+            Assert.AreEqual("fieldObjects", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateAndGetFieldNumbers_ArgumentGuards_WithNoValidFieldNumbers_ThrowsArgumentException()
+        {
+            var ex = Assert.ThrowsException<ArgumentException>(
+                () => ArgumentGuards.ValidateAndGetFieldNumbers(
+                    new List<FieldObject> { null!, new FieldObject { FieldNumber = string.Empty }, new FieldObject { FieldNumber = null! } },
+                    "fieldObjects"));
+
+            Assert.AreEqual("fieldObjects", ex.ParamName);
+        }
+
+        [TestMethod]
+        public void ValidateAndGetFieldNumbers_ArgumentGuards_WithDuplicatesAndInvalidEntries_ReturnsDistinctFieldNumbers()
+        {
+            var result = ArgumentGuards.ValidateAndGetFieldNumbers(
+                new List<FieldObject>
+                {
+                    new FieldObject { FieldNumber = "100" },
+                    null!,
+                    new FieldObject { FieldNumber = string.Empty },
+                    new FieldObject { FieldNumber = "100" },
+                    new FieldObject { FieldNumber = "101" }
+                },
+                "fieldObjects");
+
+            CollectionAssert.AreEqual(new List<string> { "100", "101" }, result);
+        }
+    }
+}