Improve error triggering in sync_integration_tests

sync/test/fake_server/fake_server.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SYNC_TEST_FAKE_SERVER_FAKE_SERVER_H_
 #define SYNC_TEST_FAKE_SERVER_FAKE_SERVER_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 54 matching lines @@
   // Puts the server in a state where it acts as if authentication has
   // succeeded.
   void SetAuthenticated();
 
   // Puts the server in a state where all commands will fail with an
   // authentication error.
   void SetUnauthenticated();
 
   // Force the server to return |error_type| in the error_code field of
   // ClientToServerResponse on all subsequent sync requests. This method should
-  // not be called if TriggerActionableError has previously been called.
-  // TODO(pvalenzuela): Return a bool here to indicate whether the call
-  // succeeded.
-  void TriggerError(const sync_pb::SyncEnums::ErrorType& error_type);
+  // not be called if TriggerActionableError has previously been called. Returns
+  // true if error triggering was successfully configured.
+  bool TriggerError(const sync_pb::SyncEnums::ErrorType& error_type);
 
   // Force the server to return the given data as part of the error field of
   // ClientToServerResponse on all subsequent sync requests. This method should
-  // not be called if TriggerError has previously been called.
+  // not be called if TriggerError has previously been called. Returns true if
+  // error triggering was successfully configured.
   bool TriggerActionableError(
     const sync_pb::SyncEnums::ErrorType& error_type,
     const std::string& description,
     const std::string& url,
     const sync_pb::SyncEnums::Action& action);
 
+  // Instructs the server to send triggered errors on every other request
+  // (starting with the first one after this call). This feature can be used to
+  // test the resiliency of the client when communicating with a problematic
+  // server or flaky network connection. This method should only be called
+  // after a call to TriggerError or TriggerActionableError. Returns true if
+  // triggered error alternating was successful.
+  bool EnableAlternatingTriggeredErrors();
+
   // Adds |observer| to FakeServer's observer list. This should be called
   // before the Profile associated with |observer| is connected to the server.
   void AddObserver(Observer* observer);
 
   // Removes |observer| from the FakeServer's observer list. This method
   // must be called if AddObserver was ever called with |observer|.
   void RemoveObserver(Observer* observer);
 
   // Undoes the effects of DisableNetwork.
   void EnableNetwork();
@@ skipping 41 matching lines @@
       FakeServerEntity* entity);
 
   // Determines whether the SyncEntity with id_string |id| is a child of an
   // entity with id_string |potential_parent_id|.
   bool IsChild(const std::string& id, const std::string& potential_parent_id);
 
   // Creates and saves tombstones for all children of the entity with the given
   // |id|. A tombstone is not created for the entity itself.
   bool DeleteChildren(const std::string& id);
 
+  // Returns whether a triggered error should be sent for the request.
+  bool ShouldSendTriggeredError() const;
+
   // This is the last version number assigned to an entity. The next entity will
   // have a version number of version_ + 1.
   int64 version_;
 
   // The current store birthday value.
   std::string store_birthday_;
 
   // Whether the server should act as if incoming connections are properly
   // authenticated.
   bool authenticated_;
 
   // All SyncEntity objects saved by the server. The key value is the entity's
   // id string.
   EntityMap entities_;
 
   // All Keystore keys known to the server.
   std::vector<std::string> keystore_keys_;
 
   // Used as the error_code field of ClientToServerResponse on all responses
   // except when |triggered_actionable_error_| is set.
   sync_pb::SyncEnums::ErrorType error_type_;
 
   // Used as the error field of ClientToServerResponse when its pointer is not
   // NULL.
   scoped_ptr<sync_pb::ClientToServerResponse_Error> triggered_actionable_error_;
 
+  // These values are used in tandem to return a triggered error (either
+  // |error_type_| or |triggered_actionable_error_|) on every other request.
+  // |alternate_triggered_errors_| is set if this feature is enabled and
+  // |request_counter_| is used to send triggered errors on odd-numbered
+  // requests. Note that |request_counter_| can be reset and is not necessarily
+  // indicative of the total number of requests handled during the object's
+  // lifetime.
+  bool alternate_triggered_errors_;
+  int request_counter_;
+
   // FakeServer's observers.
   ObserverList<Observer, true> observers_;
 
   // When true, the server operates normally. When false, a failure is returned
   // on every request. This is used to simulate a network failure on the client.
   bool network_enabled_;
 };
 
 }  // namespace fake_server
 
 #endif  // SYNC_TEST_FAKE_SERVER_FAKE_SERVER_H_