test: Add comprehensive test coverage for matchesPattern built-in function

test/UnitTests/Microsoft.OData.Core.Tests/ScenarioTests/UriParser/FilterAndOrderByFunctionalTests.cs

@@ -2653,6 +2653,37 @@ public void FilterWithInOperationWithEnumsInvalidMemberNames_ThrowsIsNotValidEnu
             action.Throws<ODataException>(Error.Format(SRResources.Binder_IsNotValidEnumConstant, expectedExceptionParameter));
         }
 
+        [Fact]
+        public void MatchesPatternInFilterWithTheReturnType()
+        {
+            // Arrange & Act - Filter people whose names match capitalized pattern
+            var filterClause = ParseFilter("matchesPattern(Name, '^[A-Z][a-z]+$')", HardCodedTestModel.TestModel, HardCodedTestModel.GetPersonType(), HardCodedTestModel.GetPeopleSet());
+
+            // Assert
+            var functionCallNode = filterClause.Expression.ShouldBeSingleValueFunctionCallQueryNode("matchesPattern");
+            Assert.Equal(2, functionCallNode.Parameters.Count());
+            Assert.True(functionCallNode.TypeReference.IsBoolean());
+
+            // Verify first parameter is the Name property
+            functionCallNode.Parameters.ElementAt(0)
+                .ShouldBeSingleValuePropertyAccessQueryNode(HardCodedTestModel.GetPersonNameProp());
+
+            // Verify second parameter is the regex pattern
+            functionCallNode.Parameters.ElementAt(1).ShouldBeConstantQueryNode("^[A-Z][a-z]+$");
+        }
+
+        [Fact]
+        public void MatchesPatternInFilterWithBooleanComparison()
+        {
+            // Arrange & Act - Use matchesPattern in boolean expression
+            var filterClause = ParseFilter("matchesPattern(Name, '[0-9]+') eq true", HardCodedTestModel.TestModel, HardCodedTestModel.GetPersonType(), HardCodedTestModel.GetPeopleSet());
+
+            // Assert
+            var binaryOp = filterClause.Expression.ShouldBeBinaryOperatorNode(BinaryOperatorKind.Equal);
+            binaryOp.Left.ShouldBeSingleValueFunctionCallQueryNode("matchesPattern");
+            binaryOp.Right.ShouldBeConstantQueryNode(true);
+        }
+
         [Fact]
         public void FilterWithInOperationWithAny()
         {

test/UnitTests/Microsoft.OData.Core.Tests/UriParser/Binders/FunctionCallBinderTests.cs

@@ -1297,6 +1297,32 @@ public void CannotCallFunctionInOpenTypeSpace()
             bindOpenFunction.Throws<ODataException>(Error.Format(SRResources.FunctionCallBinder_CallingFunctionOnOpenProperty, "Fully.Qualified.Namespace.FindMyOwner"));
         }
 
+        [Fact]
+        public void MatchesPatternFunctionBindsCorrectly()
+        {
+            // Arrange
+            var arguments = new List<QueryToken>()
+            {
+                new EndPathToken("Name", new RangeVariableToken(ExpressionConstants.It)),
+                new LiteralToken(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$")
+            };
+            var token = new FunctionCallToken("matchesPattern", arguments);
+
+            // Act
+            var result = functionCallBinder.BindFunctionCall(token);
+
+            // Assert
+            var functionCallNode = result.ShouldBeSingleValueFunctionCallQueryNode("matchesPattern", EdmCoreModel.Instance.GetBoolean(false));
+            Assert.Equal(2, functionCallNode.Parameters.Count());
+            Assert.True(functionCallNode.TypeReference.IsBoolean());
+
+            // Verify first parameter is the Name property
+            functionCallNode.Parameters.ElementAt(0).ShouldBeSingleValuePropertyAccessQueryNode(HardCodedTestModel.GetPersonNameProp());
+
+            // Verify second parameter is the regex pattern
+            functionCallNode.Parameters.ElementAt(1).ShouldBeConstantQueryNode(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$");
+        }
+
         [Fact]
         public void GetUriFunction_CombineCustomFunctionsAndBuiltInFunctions()
         {