Fix test failures

src/libstore/gc.cc

@@ -691,7 +691,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
                 string name = dirent->d_name;
                 if (name == "." || name == "..") continue;
                 Path path = settings.nixStore + "/" + name;
-                if (isValidPath(path))
+                if (isStorePath(path) && isValidPath(path))
                     entries.push_back(path);
                 else
                     tryToDelete(state, path);

src/libstore/store-api.cc

@@ -17,6 +17,7 @@ bool isInStore(const Path & path)
 bool isStorePath(const Path & path)
 {
     return isInStore(path)
+        && path.size() >= settings.nixStore.size() + 1 + storePathHashLen
         && path.find('/', settings.nixStore.size() + 1) == Path::npos;
 }