Add tests for ThenInclude with TPH inheritance strategy.

tests/Ardalis.Specification.EntityFrameworkCore.Tests/Evaluators/IncludeEvaluatorTests.cs

@@ -29,6 +29,26 @@ public void QueriesMatch_GivenIncludeExpressions()
         actual.Should().Be(expected);
     }
 
+    [Fact]
+    public void QueriesMatch_GivenInheritanceModel()
+    {
+        var spec = new Specification<Bar>();
+        spec.Query
+            .Include(x => x.BarChildren)
+            .ThenInclude<Bar, BarChild, BarDerivedInfo>(x => (x as BarDerived)!.BarDerivedInfo);
+
+        var actual = _evaluator
+            .GetQuery(DbContext.Bars, spec)
+            .ToQueryString();
+
+        var expected = DbContext.Bars
+            .Include(x => x.BarChildren)
+            .ThenInclude(x => (x as BarDerived)!.BarDerivedInfo)
+            .ToQueryString();
+
+        actual.Should().Be(expected);
+    }
+
     [Fact]
     public void QueriesMatch_GivenThenIncludeWithVariousNavigationCollectionTypes()
     {

tests/Ardalis.Specification.EntityFrameworkCore.Tests/Fixture/Data/Bar.cs

@@ -0,0 +1,31 @@
+namespace Tests.Fixture;
+
+public class Bar
+{
+    public int Id { get; set; }
+    public string? Dummy { get; set; }
+
+    private readonly List<BarChild> _barChildren = [];
+    public IReadOnlyCollection<BarChild> BarChildren => _barChildren.AsReadOnly();
+}
+
+public class BarChild
+{
+    public int Id { get; set; }
+    public string? Dummy { get; set; }
+
+    public int BarId { get; set; }
+    public Bar Bar { get; set; } = default!;
+}
+
+public class BarDerived : BarChild
+{
+    public int BarDerivedInfoId { get; set; }
+    public BarDerivedInfo BarDerivedInfo { get; set; } = default!;
+}
+
+public class BarDerivedInfo
+{
+    public int Id { get; set; }
+    public string? Name { get; set; }
+}

tests/Ardalis.Specification.EntityFrameworkCore.Tests/Fixture/TestDbContext.cs

@@ -2,6 +2,7 @@
 
 public class TestDbContext(DbContextOptions options) : DbContext(options)
 {
+    public DbSet<Bar> Bars => Set<Bar>();
     public DbSet<Foo> Foos => Set<Foo>();
     public DbSet<Country> Countries => Set<Country>();
     public DbSet<Company> Companies => Set<Company>();
@@ -23,5 +24,8 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
 
         modelBuilder.Entity<Country>()
             .HasQueryFilter(x => !x.IsDeleted);
+
+        modelBuilder.Entity<BarDerived>()
+            .HasBaseType<BarChild>();
     }
 }