CSHARP-4140: Skip $getField tests on older servers.

Author: rstam

src/MongoDB.Driver.Core/Core/Misc/Feature.cs

@@ -69,6 +69,7 @@ public class Feature
         private static readonly Feature __findAndModifyWriteConcern = new Feature("FindAndModifyWriteConcern", WireVersion.Server32);
         private static readonly Feature __findCommand = new Feature("FindCommand", WireVersion.Server32);
         private static readonly Feature __geoNearCommand = new Feature("GeoNearCommand", WireVersion.Zero, WireVersion.Server42);
+        private static readonly Feature __getField = new Feature("GetField", WireVersion.Server50);
         private static readonly Feature __getMoreComment = new Feature("GetMoreComment", WireVersion.Server44);
         private static readonly Feature __groupCommand = new Feature("GroupCommand", WireVersion.Zero, WireVersion.Server42);
         private static readonly Feature __hedgedReads = new Feature("HedgedReads", WireVersion.Server44);
@@ -369,6 +370,11 @@ public class Feature
         /// </summary>
         public static Feature GeoNearCommand => __geoNearCommand;
 
+        /// <summary>
+        /// Gets the getField feature.
+        /// </summary>
+        public static Feature GetField => __getField;
+
         /// <summary>
         /// Gets the getMore comment feature.
         /// </summary>

tests/MongoDB.Driver.Tests/Linq/Linq3ImplementationTests/Jira/CSharp4140Tests.cs

@@ -16,6 +16,8 @@
 using System.Linq;
 using FluentAssertions;
 using MongoDB.Bson;
+using MongoDB.Driver.Core.Misc;
+using MongoDB.Driver.Core.TestHelpers.XunitExtensions;
 using Xunit;
 
 namespace MongoDB.Driver.Tests.Linq.Linq3ImplementationTests.Jira
@@ -48,6 +50,8 @@ public void Should_not_use_getField(string fieldName)
         [InlineData("a.")]
         public void Should_use_getField(string fieldName)
         {
+            RequireServer.Check().Supports(Feature.GetField);
+
             var collection = GetCollection<BsonDocument>();
             CreateCollection(collection, new BsonDocument(fieldName, 123));
             var queryable = collection.AsQueryable()
@@ -67,6 +71,8 @@ public void Should_use_getField(string fieldName)
         [InlineData("$a$")]
         public void Should_use_getField_with_literal(string fieldName)
         {
+            RequireServer.Check().Supports(Feature.GetField);
+
             var collection = GetCollection<BsonDocument>();
             CreateCollection(collection, new BsonDocument(fieldName, 123));
             var queryable = collection.AsQueryable()