Improve test assertions: verify expected result counts for Instant comparisons

Agent-Logs-Url: https://github.com/zzzprojects/System.Linq.Dynamic.Core/sessions/b497145d-ba3d-430a-b608-eda596efffdd

Co-authored-by: StefH <249938+StefH@users.noreply.github.com>

Author: Copilot

test/System.Linq.Dynamic.Core.Tests/TypeConvertors/NodaTimeConverterTests.cs

@@ -165,11 +165,11 @@ private class EntityWithInstant
         }
 
         [Theory]
-        [InlineData(">")]
-        [InlineData(">=")]
-        [InlineData("<")]
-        [InlineData("<=")]
-        public void FilterByInstant_WithRelationalOperator(string op)
+        [InlineData(">", 1)]
+        [InlineData(">=", 2)]
+        [InlineData("<", 1)]
+        [InlineData("<=", 2)]
+        public void FilterByInstant_WithRelationalOperator(string op, int expectedCount)
         {
             // Arrange
             var now = SystemClock.Instance.GetCurrentInstant();
@@ -184,15 +184,15 @@ public void FilterByInstant_WithRelationalOperator(string op)
             var result = data.Where($"Timestamp {op} @0", now).ToList();
 
             // Assert
-            result.Should().NotBeNull();
+            result.Should().HaveCount(expectedCount);
         }
 
         [Theory]
-        [InlineData(">")]
-        [InlineData(">=")]
-        [InlineData("<")]
-        [InlineData("<=")]
-        public void FilterByNullableInstant_WithRelationalOperator(string op)
+        [InlineData(">", 1)]
+        [InlineData(">=", 2)]
+        [InlineData("<", 1)]
+        [InlineData("<=", 2)]
+        public void FilterByNullableInstant_WithRelationalOperator(string op, int expectedCount)
         {
             // Arrange
             var now = SystemClock.Instance.GetCurrentInstant();
@@ -207,8 +207,8 @@ public void FilterByNullableInstant_WithRelationalOperator(string op)
             // Act
             var result = data.Where($"TimestampNullable {op} @0", now).ToList();
 
-            // Assert
-            result.Should().NotBeNull();
+            // Assert - null values are excluded from comparison results
+            result.Should().HaveCount(expectedCount);
         }
 
         public class LocalDateConverter : TypeConverter