4 files changed, 130 insertions, 4 deletions
diff --git a/src/mongo/s/SConscript b/src/mongo/s/SConscript
index 1e7dfd571b5..b078f91ba3b 100644
--- a/src/mongo/s/SConscript
+++ b/src/mongo/s/SConscript
@@ -240,6 +240,7 @@ env.Library(
     source=[
         'sharding_test_fixture_common.cpp',
         'catalog_cache_loader_mock.cpp',
+        'catalog_cache_mock.cpp'
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/client/remote_command_targeter_mock',
diff --git a/src/mongo/s/catalog_cache.h b/src/mongo/s/catalog_cache.h
index 0d8143dbdbb..9dd31c65fa7 100644
--- a/src/mongo/s/catalog_cache.h
+++ b/src/mongo/s/catalog_cache.h
@@ -152,7 +152,7 @@ class CatalogCache {
 
 public:
     CatalogCache(ServiceContext* service, CatalogCacheLoader& cacheLoader);
-    ~CatalogCache();
+    virtual ~CatalogCache();
 
     /**
      * Blocking method that ensures the specified database is in the cache, loading it if necessary,
@@ -186,9 +186,9 @@ public:
      * guaranteed to never return StaleClusterTime, because the latest routing information should
      * always be available.
      */
-    StatusWith<ChunkManager> getCollectionRoutingInfo(OperationContext* opCtx,
-                                                      const NamespaceString& nss,
-                                                      bool allowLocks = false);
+    virtual StatusWith<ChunkManager> getCollectionRoutingInfo(OperationContext* opCtx,
+                                                              const NamespaceString& nss,
+                                                              bool allowLocks = false);
 
     /**
      * Same as getDatbase above, but in addition forces the database entry to be refreshed.
diff --git a/src/mongo/s/catalog_cache_mock.cpp b/src/mongo/s/catalog_cache_mock.cpp
new file mode 100644
index 00000000000..706b6a836d8
--- /dev/null
+++ b/src/mongo/s/catalog_cache_mock.cpp
@@ -0,0 +1,61 @@
+/**
+ *    Copyright (C) 2021-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/s/catalog_cache_mock.h"
+#include "mongo/db/service_context.h"
+#include "mongo/s/catalog_cache_loader_mock.h"
+
+namespace mongo {
+
+const Status CatalogCacheMock::kChunkManagerInternalErrorStatus = {
+    ErrorCodes::InternalError, "Mocked catalog cache received unexpected chunks manager"};
+
+
+CatalogCacheMock::CatalogCacheMock(ServiceContext* serviceContext, CatalogCacheLoaderMock& loader)
+    : CatalogCache(serviceContext, loader) {}
+
+StatusWith<ChunkManager> CatalogCacheMock::getCollectionRoutingInfo(OperationContext* opCtx,
+                                                                    const NamespaceString& nss,
+                                                                    bool allowLocks) {
+    return _swChunkManagerReturnValue;
+}
+
+void CatalogCacheMock::setChunkManagerReturnValue(StatusWith<ChunkManager> statusWithChunks) {
+    _swChunkManagerReturnValue = statusWithChunks;
+}
+void CatalogCacheMock::clearChunkManagerReturnValue() {
+    _swChunkManagerReturnValue = kChunkManagerInternalErrorStatus;
+}
+
+std::unique_ptr<CatalogCacheMock> CatalogCacheMock::make() {
+    auto catalogCacheLoader = std::make_unique<CatalogCacheLoaderMock>();
+    auto serviceContext = ServiceContext::make();
+    return std::make_unique<CatalogCacheMock>(serviceContext.get(), *catalogCacheLoader);
+}
+}  // namespace mongo
diff --git a/src/mongo/s/catalog_cache_mock.h b/src/mongo/s/catalog_cache_mock.h
new file mode 100644
index 00000000000..306529b60d3
--- /dev/null
+++ b/src/mongo/s/catalog_cache_mock.h
@@ -0,0 +1,64 @@
+/**
+ *    Copyright (C) 2021-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/s/catalog_cache.h"
+#include "mongo/s/catalog_cache_loader_mock.h"
+
+namespace mongo {
+
+/**
+ * Mocks the metadata refresh results with settable return values. The purpose of this class is to
+ * facilitate testing of classes that use a CatalogCacheLoader.
+ */
+class CatalogCacheMock final : public CatalogCache {
+    CatalogCacheMock(const CatalogCacheMock&) = delete;
+    CatalogCacheMock& operator=(const CatalogCacheMock&) = delete;
+
+public:
+    CatalogCacheMock(ServiceContext* context, CatalogCacheLoaderMock& loader);
+    ~CatalogCacheMock() = default;
+
+    StatusWith<ChunkManager> getCollectionRoutingInfo(OperationContext* opCtx,
+                                                      const NamespaceString& nss,
+                                                      bool allowLocks) override;
+
+    void setChunkManagerReturnValue(StatusWith<ChunkManager> statusWithChunks);
+    void clearChunkManagerReturnValue();
+
+    static std::unique_ptr<CatalogCacheMock> make();
+
+    static const Status kChunkManagerInternalErrorStatus;
+
+private:
+    StatusWith<ChunkManager> _swChunkManagerReturnValue{kChunkManagerInternalErrorStatus};
+};
+
+}  // namespace mongo