diff --git a/testing-auditing.md b/testing-auditing.md
index f55e7e1..cc4e314 100644
--- a/testing-auditing.md
+++ b/testing-auditing.md
@@ -1,4 +1,13 @@
-# todo
+# Testing and Auditing
+
+Make sure all the codes and branches of your contracts are covered with tests. If your contracts interact with interoperable systems (e.g. oracles, cross-chain bridges), make sure you run integration tests with them.
+
+#### Testing with private net
+
+Use [neo-express](https://github.com/neo-project/neo-express)
+
+#### Testing on testnet and mainnet
+
+Use [neo-fairy-test](https://github.com/Hecate2/neo-fairy-test/)
 
-* introduce the Hecate2's testing tool
 * introduce some famous auditing team on N3