Add unit test to show workaround for object.Equals

Author: StefH

test/System.Linq.Dynamic.Core.Tests/Parser/ExpressionParserTests.cs

@@ -35,7 +35,7 @@ public class MyView
     public ExpressionParserTests()
     {
         _dynamicTypeProviderMock = new Mock<IDynamicLinkCustomTypeProvider>();
-        _dynamicTypeProviderMock.Setup(dt => dt.GetCustomTypes()).Returns(new HashSet<Type>() { typeof(Company), typeof(MainCompany) });
+        _dynamicTypeProviderMock.Setup(dt => dt.GetCustomTypes()).Returns([typeof(Company), typeof(MainCompany)]);
         _dynamicTypeProviderMock.Setup(dt => dt.ResolveType(typeof(Company).FullName!)).Returns(typeof(Company));
         _dynamicTypeProviderMock.Setup(dt => dt.ResolveType(typeof(MainCompany).FullName!)).Returns(typeof(MainCompany));
         _dynamicTypeProviderMock.Setup(dt => dt.ResolveTypeBySimpleName("Company")).Returns(typeof(Company));
@@ -346,7 +346,7 @@ public void Parse_NullableShouldReturnNullable(string expression, object resultT
     [Theory]
     [InlineData("it.MainCompany.Name != null", "(company.MainCompany.Name != null)")]
     [InlineData("@MainCompany.Companies.Count() > 0", "(company.MainCompany.Companies.Count() > 0)")]
-    // [InlineData("Company.Equals(null, null)", "Equals(null, null)")] issue 867
+    // [InlineData("Company.Equals(null, null)", "Equals(null, null)")]
     [InlineData("MainCompany.Name", "company.MainCompany.Name")]
     [InlineData("Name", "company.Name")]
     [InlineData("company.Name", "company.Name")]
@@ -377,6 +377,39 @@ public void Parse_When_PrioritizePropertyOrFieldOverTheType_IsTrue(string expres
         parsedExpression.Should().Be(result);
     }
 
+    [Theory]
+    [InlineData("object.Equals(null, null)", "Equals(null, null)")]
+    [InlineData("Company.Equals(null, null)", "Equals(null, null)")]
+    public void Parse_Object_Equals_867_Workaround(string expression, string result)
+    {
+        // Arrange
+        var config = new ParsingConfig
+        {
+            IsCaseSensitive = true,
+            CustomTypeProvider = _dynamicTypeProviderMock.Object
+        };
+        _dynamicTypeProviderMock
+            .Setup(dt => dt.GetCustomTypes())
+            .Returns([typeof(Company), typeof(MainCompany), typeof(object)]);
+
+        ParameterExpression[] parameters = [ParameterExpressionHelper.CreateParameterExpression(typeof(Company), "company")];
+        var sut = new ExpressionParser(parameters, expression, null, config);
+
+        // Act
+        string parsedExpression;
+        try
+        {
+            parsedExpression = sut.Parse(null).ToString();
+        }
+        catch (ParseException e)
+        {
+            parsedExpression = e.Message;
+        }
+
+        // Assert
+        parsedExpression.Should().Be(result);
+    }
+
     [Theory]
     [InlineData("it.MainCompany.Name != null", "(company.MainCompany.Name != null)")]
     [InlineData("@MainCompany.Companies.Count() > 0", "(company.MainCompany.Companies.Count() > 0)")]