fix(tests): will currently detect wrong attempts to access deleted files

with virtual files we may wrongly try to access a file we just deleted

in which case an assert should ensure we capture this during automated
tests

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

src/libsync/vfs/cfapi/cfapiwrapper.cpp

@@ -780,6 +780,7 @@ OCC::CfApiWrapper::FileHandle OCC::CfApiWrapper::handleForPath(const QString &pa
 
     if (!FileSystem::fileExists(path)) {
         qCWarning(lcCfApiWrapper) << "does not exist" << path;
+        Q_ASSERT(false);
         return {};
     }