Don't run Select_nested_projection without MARS

test/EFCore.Cosmos.FunctionalTests/Query/SimpleQueryCosmosTest.Select.cs

@@ -257,12 +257,6 @@ FROM root c
 WHERE ((c[""Discriminator""] = ""Customer"") AND (c[""City""] = ""London""))");
         }
 
-        [ConditionalTheory(Skip = "Issue #16143")]
-        public override void Select_nested_projection()
-        {
-            base.Select_nested_projection();
-        }
-
         public override async Task Select_nested_collection(bool isAsync)
         {
             await base.Select_nested_collection(isAsync);

test/EFCore.Specification.Tests/Query/SimpleQueryTestBase.Select.cs

@@ -408,32 +408,6 @@ from c in cs
                     select c.City);
         }
 
-        [ConditionalFact]
-        public virtual void Select_nested_projection()
-        {
-            using (var context = CreateContext())
-            {
-                var customers = context.Customers
-                    .Where(c => c.CustomerID.StartsWith("A"))
-                    .Select(c => new
-                    {
-                        Customer = c,
-                        CustomerAgain = Get(context, c.CustomerID)
-                    })
-                    .ToList();
-
-                Assert.Equal(4, customers.Count);
-
-                foreach (var customer in customers)
-                {
-                    Assert.Same(customer.Customer, customer.CustomerAgain);
-                }
-            }
-        }
-
-        private static Customer Get(NorthwindContext context, string id)
-          => context.Customers.Single(c => c.CustomerID == id);
-
         [ConditionalTheory(Skip = "Issue#16314")]
         [MemberData(nameof(IsAsyncData))]
         public virtual Task Select_nested_collection(bool isAsync)

test/EFCore.SqlServer.FunctionalTests/Query/QueryBugsTest.cs

@@ -6071,6 +6071,67 @@ public class Repo15518
 
         #endregion
 
+        #region Bug8864
+
+        [ConditionalFact]
+        public virtual void Select_nested_projection()
+        {
+            using (CreateDatabase8864())
+            {
+                using (var context = new MyContext8864(_options))
+                {
+                    var customers = context.Customers
+                        .Select(c => new
+                        {
+                            Customer = c,
+                            CustomerAgain = Get(context, c.Id)
+                        })
+                        .ToList();
+
+                    Assert.Equal(2, customers.Count);
+
+                    foreach (var customer in customers)
+                    {
+                        Assert.Same(customer.Customer, customer.CustomerAgain);
+                    }
+                }
+            }
+        }
+
+        private static Customer8864 Get(MyContext8864 context, int id)
+          => context.Customers.Single(c => c.Id == id);
+
+        private SqlServerTestStore CreateDatabase8864()
+            => CreateTestStore(
+                () => new MyContext8864(_options),
+                context =>
+                {
+                    context.AddRange(
+                        new Customer8864 { Name = "Alan" },
+                        new Customer8864 { Name = "Elon" });
+
+                    context.SaveChanges();
+
+                    ClearLog();
+                });
+
+        public class MyContext8864 : DbContext
+        {
+            public DbSet<Customer8864> Customers { get; set; }
+
+            public MyContext8864(DbContextOptions options) : base(options)
+            {
+            }
+        }
+
+        public class Customer8864
+        {
+            public int Id { get; set; }
+            public string Name { get; set; }
+        }
+
+        #endregion
+
         private DbContextOptions _options;
 
         private SqlServerTestStore CreateTestStore<TContext>(

test/EFCore.SqlServer.FunctionalTests/Query/SimpleQuerySqlServerTest.Select.cs

@@ -1007,11 +1007,5 @@ public override async Task SelectMany_without_result_selector_collection_navigat
 FROM [Customers] AS [c]
 INNER JOIN [Orders] AS [o] ON [c].[CustomerID] = [o].[CustomerID]");
         }
-
-        [ConditionalFact(Skip = "Issue#17117")]
-        public override void Select_nested_projection()
-        {
-            base.Select_nested_projection();
-        }
     }
 }