diff --git a/tests/unit_tests/hardfork.cpp b/tests/unit_tests/hardfork.cpp
index 82b1a33f..97f08a49 100644
--- a/tests/unit_tests/hardfork.cpp
+++ b/tests/unit_tests/hardfork.cpp
@@ -102,6 +102,7 @@ public:
   virtual bool for_all_blocks(std::function<bool(uint64_t, const crypto::hash&, const cryptonote::block&)>) const { return true; }
   virtual bool for_all_transactions(std::function<bool(const crypto::hash&, const cryptonote::transaction&)>) const { return true; }
   virtual bool for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, size_t tx_idx)> f) const { return true; }
+  virtual bool is_read_only() const { return false; }
 
   virtual void add_block( const block& blk
                         , const size_t& block_size