1 files changed, 4 insertions, 4 deletions
diff --git a/packages/contracts/test/utils/match_order_tester.ts b/packages/contracts/test/utils/match_order_tester.ts
index 6145779b0..0d5ad5e9f 100644
--- a/packages/contracts/test/utils/match_order_tester.ts
+++ b/packages/contracts/test/utils/match_order_tester.ts
@@ -14,10 +14,10 @@ chaiSetup.configure();
 const expect = chai.expect;
 
 export class MatchOrderTester {
-    private _exchangeWrapper: ExchangeWrapper;
-    private _erc20Wrapper: ERC20Wrapper;
-    private _erc721Wrapper: ERC721Wrapper;
-    private _feeTokenAddress: string;
+    private readonly _exchangeWrapper: ExchangeWrapper;
+    private readonly _erc20Wrapper: ERC20Wrapper;
+    private readonly _erc721Wrapper: ERC721Wrapper;
+    private readonly _feeTokenAddress: string;
 
     /// @dev Compares a pair of ERC20 balances and a pair of ERC721 token owners.
     /// @param expectedNewERC20BalancesByOwner Expected ERC20 balances.