Add tests for singlet links and update comments for clarity

Author: konard

csharp/Platform.Protocols.Lino.Tests/EdgeCaseParserTests.cs

@@ -81,6 +81,50 @@ public static void TestAllFeaturesTest()
             Assert.NotEmpty(result);
         }
 
+        [Fact]
+        public static void TestSingletLinks()
+        {
+            // Test singlet (1)
+            var input = "(1)";
+            var result = new Parser().Parse(input);
+            Assert.Single(result);
+            Assert.Equal("1", result[0].Id);
+            Assert.Null(result[0].Values);
+
+            // Test (1 2)
+            input = "(1 2)";
+            result = new Parser().Parse(input);
+            Assert.Single(result);
+            Assert.Null(result[0].Id);
+            Assert.NotNull(result[0].Values);
+            Assert.Equal(2, result[0].Values.Count);
+            Assert.Equal("1", result[0].Values[0].Id);
+            Assert.Equal("2", result[0].Values[1].Id);
+
+            // Test (1 2 3)
+            input = "(1 2 3)";
+            result = new Parser().Parse(input);
+            Assert.Single(result);
+            Assert.Null(result[0].Id);
+            Assert.NotNull(result[0].Values);
+            Assert.Equal(3, result[0].Values.Count);
+            Assert.Equal("1", result[0].Values[0].Id);
+            Assert.Equal("2", result[0].Values[1].Id);
+            Assert.Equal("3", result[0].Values[2].Id);
+
+            // Test (1 2 3 4)
+            input = "(1 2 3 4)";
+            result = new Parser().Parse(input);
+            Assert.Single(result);
+            Assert.Null(result[0].Id);
+            Assert.NotNull(result[0].Values);
+            Assert.Equal(4, result[0].Values.Count);
+            Assert.Equal("1", result[0].Values[0].Id);
+            Assert.Equal("2", result[0].Values[1].Id);
+            Assert.Equal("3", result[0].Values[2].Id);
+            Assert.Equal("4", result[0].Values[3].Id);
+        }
+
         [Fact]
         public static void TestEmptyDocumentTest()
         {

csharp/Platform.Protocols.Lino.Tests/SingleLineParserTests.cs

@@ -64,10 +64,10 @@ public static void ParseSimpleReferenceTest()
             var links = parser.Parse(source);
             Assert.NotNull(links);
             Assert.Single(links);
-            // Simple reference without colon creates a link with that ID
+            // Simple reference creates a singlet link with that ID
             Assert.Equal("test", links[0]!.Id);
-            // Values can be null for simple references
-            Assert.True(links[0].Values?.Count == 0 || links[0].Values == null);
+            // Values should be null for singlet links
+            Assert.Null(links[0].Values);
         }
 
         [Fact]