Test duplicated join on some Linq queries

Test for nhibernate#1962

Author: fredericDelaporte

src/NHibernate.Test/Async/NHSpecificTest/GH1962/Fixture.cs

@@ -0,0 +1,36 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by AsyncGenerator.
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+
+using System.Linq;
+using NUnit.Framework;
+using NHibernate.Linq;
+
+namespace NHibernate.Test.NHSpecificTest.GH1962
+{
+	using System.Threading.Tasks;
+	[TestFixture]
+	public class FixtureAsync : BugTestCase
+	{
+		[Test]
+		[KnownBug("#1962")]
+		public async Task LinqShouldBeValidAsync()
+		{
+			using (var session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				var result =
+					await (session
+						.Query<Product>()
+						.CountAsync(p => p.OrderDetails.Any(od => od.Order.OrderDetails[0] == od)));
+				Assert.That(result, Is.EqualTo(0));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH1962/Entity.cs

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+using System.Collections.Generic;
+
+namespace NHibernate.Test.NHSpecificTest.GH1962
+{
+	public class Order
+	{
+		public virtual int Id { get; protected set; }
+
+		public virtual IList<OrderDetail> OrderDetails { get; protected set; } = new List<OrderDetail>();
+	}
+
+	public class Product
+	{
+		public virtual int Id { get; protected set; }
+		public virtual string Name { get; protected set; }
+
+		public virtual IList<OrderDetail> OrderDetails { get; protected set; } = new List<OrderDetail>();
+	}
+
+	public class OrderDetail
+	{
+		public virtual int Id { get; protected set; }
+
+		public virtual Order Order { get; protected set; }
+		public virtual Product Product { get; protected set; }
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH1962/Fixture.cs

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+using System.Linq;
+using NUnit.Framework;
+
+namespace NHibernate.Test.NHSpecificTest.GH1962
+{
+	[TestFixture]
+	public class Fixture : BugTestCase
+	{
+		[Test]
+		[KnownBug("#1962")]
+		public void LinqShouldBeValid()
+		{
+			using (var session = OpenSession())
+			using (session.BeginTransaction())
+			{
+				var result =
+					session
+						.Query<Product>()
+						.Count(p => p.OrderDetails.Any(od => od.Order.OrderDetails[0] == od));
+				Assert.That(result, Is.EqualTo(0));
+			}
+		}
+	}
+}

src/NHibernate.Test/NHSpecificTest/GH1962/Mappings.hbm.xml

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+<?xml version="1.0" encoding="utf-8" ?>
+<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernate.Test"
+                   namespace="NHibernate.Test.NHSpecificTest.GH1962">
+
+  <class name='Order' table='ORDERS'>
+    <id name='Id' column='ORDER_ID'>
+      <generator class='assigned'/>
+    </id>
+
+    <list name='OrderDetails' lazy="false" inverse='false' table='ORDER_DETAILS'>
+      <key column='ORDER_ID'/>
+      <index column='INDEX_NUMBER'/>
+      <one-to-many class='OrderDetail'/>
+    </list>
+
+  </class>
+
+  <class name='Product' table='PRODUCTS'>
+    <id name='Id' column='PRODUCT_ID'>
+      <generator class='assigned'/>
+    </id>
+    <property name='Name' column='NAME'/>
+
+    <bag name='OrderDetails' lazy="false" inverse='true' table='ORDER_DETAILS'>
+      <key column='PRODUCT_ID'/>
+      <one-to-many class='OrderDetail'/>
+    </bag>
+
+  </class>
+
+  <class name='OrderDetail' table='ORDER_DETAILS'>
+    <id name='Id' column='ORDER_DETAIL_ID'>
+      <generator class='assigned'/>
+    </id>
+
+    <many-to-one name='Order' class='Order' column='ORDER_ID'/>
+    <many-to-one name='Product' class='Product' column='PRODUCT_ID'/>
+
+  </class>
+
+</hibernate-mapping>