Fix broken tests

Author: Oleksandr Poliakov

src/MongoDB.Driver/MongoClient.cs

@@ -104,7 +104,7 @@ public MongoClient(string connectionString)
         internal MongoClient(IOperationExecutor operationExecutor, MongoClientSettings settings)
             : this(settings)
         {
-            _operationExecutor = operationExecutor;
+            _operationExecutor = new OperationExecutorWrapper(operationExecutor);
         }
 
         // public properties
@@ -442,7 +442,7 @@ public IMongoClient WithReadConcern(ReadConcern readConcern)
 
             var newSettings = Settings.Clone();
             newSettings.ReadConcern = readConcern;
-            return new MongoClient(newSettings);
+            return new MongoClient(_operationExecutor, newSettings);
         }
 
         /// <inheritdoc/>
@@ -454,7 +454,7 @@ public IMongoClient WithReadPreference(ReadPreference readPreference)
 
             var newSettings = Settings.Clone();
             newSettings.ReadPreference = readPreference;
-            return new MongoClient(newSettings);
+            return new MongoClient(_operationExecutor, newSettings);
         }
 
         /// <inheritdoc/>
@@ -466,7 +466,7 @@ public IMongoClient WithWriteConcern(WriteConcern writeConcern)
 
             var newSettings = Settings.Clone();
             newSettings.WriteConcern = writeConcern;
-            return new MongoClient(newSettings);
+            return new MongoClient(_operationExecutor, newSettings);
         }
 
         // private methods

src/MongoDB.Driver/OperationExecutorWrapper.cs

@@ -0,0 +1,102 @@
+/* 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.Threading;
+using System.Threading.Tasks;
+using MongoDB.Driver.Core.Operations;
+
+namespace MongoDB.Driver
+{
+    /// <summary>
+    /// Wraps provided IOperationExecutor to preserve it from disposal.
+    /// Used by MongoClient when IOperationExecutor is injected from outside.
+    /// </summary>
+    internal sealed class OperationExecutorWrapper : IOperationExecutor
+    {
+        private readonly IOperationExecutor _wrappedExecutor;
+        private bool _isDisposed;
+
+        public OperationExecutorWrapper(IOperationExecutor executor)
+        {
+            _wrappedExecutor = executor;
+        }
+
+        public void Dispose()
+        {
+            _isDisposed = true;
+        }
+
+        public TResult ExecuteReadOperation<TResult>(
+            IReadOperation<TResult> operation,
+            ReadOperationOptions options,
+            IClientSessionHandle session = null,
+            CancellationToken cancellationToken = default)
+        {
+            ThrowIfDisposed();
+            return _wrappedExecutor.ExecuteReadOperation(operation, options, session, cancellationToken);
+        }
+
+        public Task<TResult> ExecuteReadOperationAsync<TResult>(
+            IReadOperation<TResult> operation,
+            ReadOperationOptions options,
+            IClientSessionHandle session = null,
+            CancellationToken cancellationToken = default)
+        {
+            ThrowIfDisposed();
+            return _wrappedExecutor.ExecuteReadOperationAsync(operation, options, session, cancellationToken);
+        }
+
+        public TResult ExecuteWriteOperation<TResult>(
+            IWriteOperation<TResult> operation,
+            WriteOperationOptions options,
+            IClientSessionHandle session = null,
+            CancellationToken cancellationToken = default)
+        {
+            ThrowIfDisposed();
+            return _wrappedExecutor.ExecuteWriteOperation(operation, options, session, cancellationToken);
+        }
+
+        public Task<TResult> ExecuteWriteOperationAsync<TResult>(
+            IWriteOperation<TResult> operation,
+            WriteOperationOptions options,
+            IClientSessionHandle session = null,
+            CancellationToken cancellationToken = default)
+        {
+            ThrowIfDisposed();
+            return _wrappedExecutor.ExecuteWriteOperationAsync(operation, options, session, cancellationToken);
+        }
+
+        public IClientSessionHandle StartImplicitSession(CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+            return _wrappedExecutor.StartImplicitSession(cancellationToken);
+        }
+
+        public Task<IClientSessionHandle> StartImplicitSessionAsync(CancellationToken cancellationToken)
+        {
+            ThrowIfDisposed();
+            return _wrappedExecutor.StartImplicitSessionAsync(cancellationToken);
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (_isDisposed)
+            {
+                throw new ObjectDisposedException(nameof(OperationExecutorWrapper));
+            }
+        }
+    }
+}