CSHARP-4049: Verify that issue is not present in LINQ3. (#841)

Author: rstam

tests/MongoDB.Driver.Tests/Linq/Linq3ImplementationTests/Jira/CSharp4049Tests.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.Linq;
+using FluentAssertions;
+using MongoDB.Bson.Serialization.Attributes;
+using Xunit;
+
+namespace MongoDB.Driver.Tests.Linq.Linq3ImplementationTests.Jira
+{
+    public class CSharp4049Tests : Linq3IntegrationTest
+    {
+        [Fact]
+        public void Aggregate_Project_should_translate_as_expected()
+        {
+            var collection = CreateCollection();
+            var aggregate = collection.Aggregate()
+                .Project(x => new TestClass { Property = x.Property.ToUpper() });
+
+            var stages = Translate(collection, aggregate);
+            AssertStages(stages, "{ $project : { _p : { $toUpper : '$_p' }, _id : 0 } }");
+
+            var results = aggregate.ToList().Single();
+            results.Property.Should().Be("ABC");
+        }
+
+        [Fact]
+        public void Queryable_Select_should_translate_as_expected()
+        {
+            var collection = CreateCollection();
+            var queryable = collection.AsQueryable()
+                .Select(x => new TestClass { Property = x.Property.ToUpper() });
+
+            var stages = Translate(collection, queryable);
+            AssertStages(stages, "{ $project : { _p : { $toUpper : '$_p' }, _id : 0 } }");
+
+            var results = queryable.ToList().Single();
+            results.Property.Should().Be("ABC");
+        }
+
+        private IMongoCollection<TestClass> CreateCollection()
+        {
+            var collection = GetCollection<TestClass>();
+
+            var documents = new[]
+            {
+                new TestClass { Property = "abc" }
+            };
+            CreateCollection(collection, documents);
+
+            return collection;
+        }
+
+        public class TestClass
+        {
+            [BsonElement("_p")]
+            public string Property { get; set; }
+        }
+    }
+}