1 files changed, 1 insertions, 1 deletions
diff --git a/packages/order-watcher/test/utils/token_utils.ts b/packages/order-watcher/test/utils/token_utils.ts
index e1191b5bb..f91b3797f 100644
--- a/packages/order-watcher/test/utils/token_utils.ts
+++ b/packages/order-watcher/test/utils/token_utils.ts
@@ -7,7 +7,7 @@ const PROTOCOL_TOKEN_SYMBOL = 'ZRX';
 const WETH_TOKEN_SYMBOL = 'WETH';
 
 export class TokenUtils {
-    private _tokens: Token[];
+    private readonly _tokens: Token[];
     constructor(tokens: Token[]) {
         this._tokens = tokens;
     }