Add Enum support in keyset

- add expression for converting enum to it's underlying type

src/MR.EntityFrameworkCore.KeysetPagination/KeysetFilterPredicateStrategy.cs

@@ -92,11 +92,23 @@ protected static BinaryExpression MakeComparisonExpression<T>(
 		else
 		{
 			return compare(
-				memberAccess,
-				EnsureMatchingType(memberAccess, referenceValue));
+				EnsureEnumIsConvertedToUnderlyingType(memberAccess),
+				EnsureEnumIsConvertedToUnderlyingType(EnsureMatchingType(memberAccess, referenceValue)));
 		}
 	}
 
+	private static Expression EnsureEnumIsConvertedToUnderlyingType(Expression memberAccess)
+	{
+		if (memberAccess.Type.IsEnum)
+		{
+			var enumUnderlyingType = Enum.GetUnderlyingType(memberAccess.Type);
+
+			return Expression.Convert(memberAccess, enumUnderlyingType);
+		}
+
+		return memberAccess;
+	}
+
 	protected static Expression EnsureMatchingType(
 		Expression memberExpression,
 		Expression targetExpression)

test/MR.EntityFrameworkCore.KeysetPagination.Tests/DatabaseFixture.cs

@@ -79,6 +79,7 @@ private void Seed(TestDbContext context)
 					Created = created,
 				},
 				Inners2 = Enumerable.Range(0, rand.Next(10)).Select(i => new NestedInner2Model()).ToList(),
+				EnumValue = i % 2 == 0 ? EnumType.Value1 : EnumType.Value2,
 			});
 		}
 

test/MR.EntityFrameworkCore.KeysetPagination.Tests/KeysetPaginationTest.cs

@@ -25,6 +25,8 @@ public enum QueryType
 		NullCoalescing,
 		NullCoalescing2,
 		Count,
+		Enum,
+		NestedEnum
 	}
 
 	private const int Size = 10;
@@ -58,6 +60,8 @@ public KeysetPaginationTest(DatabaseFixture fixture)
 			QueryType.NullCoalescing => q => q.OrderBy(x => x.CreatedNullable ?? DateTime.MinValue).ThenBy(x => x.Id),
 			QueryType.NullCoalescing2 => q => q.OrderBy(x => x.CreatedNullable ?? x.Created).ThenBy(x => x.Id),
 			QueryType.Count => q => q.OrderBy(x => x.Inners2.Count).ThenBy(x => x.Id),
+			QueryType.Enum => q => q.OrderBy(x => x.EnumValue).ThenBy(x => x.Id),
+			QueryType.NestedEnum => q => q.OrderBy(x => x.Inner.NestedEnumValue).ThenBy(x => x.Id),
 			_ => throw new NotImplementedException(),
 		};
 		Action<KeysetPaginationBuilder<MainModel>> keysetPaginationBuilder = queryType switch
@@ -75,6 +79,8 @@ public KeysetPaginationTest(DatabaseFixture fixture)
 			QueryType.NullCoalescing => b => b.Ascending(x => x.CreatedNullable ?? DateTime.MinValue).Ascending(x => x.Id),
 			QueryType.NullCoalescing2 => b => b.Ascending(x => x.CreatedNullable ?? x.Created).Ascending(x => x.Id),
 			QueryType.Count => b => b.Ascending(x => x.Inners2.Count).Ascending(x => x.Id),
+			QueryType.Enum => q => q.Ascending(x => x.EnumValue).Ascending(x => x.Id),
+			QueryType.NestedEnum => q => q.Ascending(x => x.Inner.NestedEnumValue).Ascending(x => x.Id),
 			_ => throw new NotImplementedException(),
 		};
 

test/MR.EntityFrameworkCore.KeysetPagination.Tests/TestModels/MainModel.cs

@@ -22,6 +22,7 @@ public class MainModel
 	public DateTime? CreatedNullable { get; set; }
 
 	public DateTime CreatedComputed { get; }
+	public EnumType EnumValue { get; set; }
 
 	public NestedInnerModel Inner { get; set; }
 
@@ -34,6 +35,8 @@ public class NestedInnerModel
 	public int Id { get; set; }
 
 	public DateTime Created { get; set; }
+
+	public EnumType NestedEnumValue { get; set; }
 }
 
 public class NestedInner2Model
@@ -44,3 +47,9 @@ public class NestedInner2Model
 
 	public MainModel MainModel { get; set; }
 }
+
+public enum EnumType
+{
+	Value1,
+	Value2,
+}