CSHARP-2308: CSHARP-2308: Nested select with multiple variables in scope should translate correctly.

Author: rstam

tests/MongoDB.Driver.Tests/Linq/Linq3ImplementationTests/Jira/CSharp2308Tests.cs

@@ -0,0 +1,72 @@
+/* Copyright 2010-present MongoDB Inc.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+using System.Collections.Generic;
+using System.Linq;
+using FluentAssertions;
+using MongoDB.Bson;
+using Xunit;
+
+namespace MongoDB.Driver.Tests.Linq.Linq3ImplementationTests.Jira
+{
+    public class CSharp2308Tests
+    {
+        [Fact]
+        public void Nested_Select_should_work()
+        {
+            var client = DriverTestConfiguration.Linq3Client;
+            var database = client.GetDatabase("FooBar");
+            var collection = database.GetCollection<FooNest>("Foos");
+
+            database.DropCollection("Foos");
+
+            collection.InsertOne(
+                new FooNest
+                {
+                    Name = "Parent",
+                    NestedCollection = new[] {
+                        new FooNest {
+                            Name = "Child"
+                        }
+                    }
+                });
+
+            var queryable = collection.AsQueryable()
+                .Select(top => top.NestedCollection.Select(child => new { ParentName = top.Name, child.Name }));
+
+            var stages = Linq3TestHelpers.Translate(collection, queryable);
+            var expectedStages = new[]
+            {
+                "{ $project : { _v : { $map : { input : '$NestedCollection', as : 'child', in : { ParentName : '$Name', Name : '$$child.Name' } } }, _id : 0 } }"
+            };
+            Linq3TestHelpers.AssertStages(stages, expectedStages);
+
+            var pipelineDefinition = new BsonDocumentStagePipelineDefinition<FooNest, BsonDocument>(stages);
+            var resultAsDocument = collection.Aggregate(pipelineDefinition).ToList().Single();
+            resultAsDocument.Should().Be("{ _v : [{ ParentName : 'Parent', Name : 'Child' }] }");
+
+            var result = queryable.ToList().Single().ToList();
+            result.Should().HaveCount(1);
+            result[0].ParentName.Should().Be("Parent");
+            result[0].Name.Should().Be("Child");
+        }
+
+        public class FooNest
+        {
+            public string Name;
+            public IEnumerable<FooNest> NestedCollection;
+        }
+    }
+}