CSHARP-2472: Get sample from ticket to pass.

Author: rstam

tests/MongoDB.Driver.Tests/Linq/Linq3ImplementationTests/Jira/CSharp2472Tests.cs

@@ -0,0 +1,89 @@
+/* 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;
+using System.Linq;
+using FluentAssertions;
+using MongoDB.Driver.Linq;
+using Xunit;
+
+namespace MongoDB.Driver.Tests.Linq.Linq3ImplementationTests.Jira
+{
+    public class CSharp2472Tests : Linq3IntegrationTest
+    {
+        [Fact]
+        public void Projection_of_ArrayOfDocuments_dictionary_keys_and_values_should_work()
+        {
+            var collection = CreateCollection();
+            var equipmentId = 1;
+            var startDate = new DateTime(2022, 01, 01, 0, 0, 0, DateTimeKind.Utc);
+            var endDate = new DateTime(2022, 01, 02, 0, 0, 0, DateTimeKind.Utc);
+
+            var queryable = collection
+                .AsQueryable()
+                .Where(
+                    q => q.equipment_id == equipmentId
+                    && q.timestamp >= startDate
+                    && q.timestamp <= endDate
+                )
+                .GroupBy(g => g.timestamp)
+                .Select(p => new MyDTO
+                {
+                    timestamp = p.Key,
+                    sqrt_calc = (decimal)Math.Sqrt(
+                        p.Sum(x => (double)x.my_decimal_value)
+                    )
+                })
+                .OrderBy(q => q.timestamp);
+
+            var stages = Translate(collection, queryable);
+            AssertStages(
+                stages,
+                "{ $match : { equipment_id : 1, timestamp : { $gte : ISODate('2022-01-01T00:00:00Z'), $lte : ISODate('2022-01-02T00:00:00Z') } } }",
+                "{ $group : { _id : '$timestamp', __agg0 : { $sum : { $toDouble : '$my_decimal_value' } } } }",
+                "{ $project : { timestamp : '$_id', sqrt_calc : { $toDecimal : { $sqrt : '$__agg0' } }, _id : 0 } }",
+                "{ $sort : { timestamp : 1 } }");
+
+            var result = queryable.Single();
+            result.timestamp.Should().Be(new DateTime(2022, 01, 01, 12, 0, 0, DateTimeKind.Utc));
+            result.sqrt_calc.Should().Be(2M);
+        }
+
+        private IMongoCollection<C> CreateCollection()
+        {
+            var collection = GetCollection<C>("C");
+
+            CreateCollection(
+                collection,
+                new C { Id = 1, equipment_id = 1, timestamp = new DateTime(2022, 01, 01, 12, 0, 0, DateTimeKind.Utc), my_decimal_value = 4M });
+
+            return collection;
+        }
+
+        private class C
+        {
+            public int Id { get; set; }
+            public int equipment_id { get; set; }
+            public DateTime timestamp { get; set; }
+            public decimal my_decimal_value { get; set; }
+        }
+
+        private class MyDTO
+        {
+            public DateTime timestamp { get; set; }
+            public decimal sqrt_calc { get; set; }
+        }
+    }
+}