diff --git a/libs/remix-tests/src/runTestSources.ts b/libs/remix-tests/src/runTestSources.ts
index 6e8c0bfc82..55e6e7b123 100644
--- a/libs/remix-tests/src/runTestSources.ts
+++ b/libs/remix-tests/src/runTestSources.ts
@@ -31,7 +31,7 @@ export class UnitTestRunner {
 
   async createWeb3Provider (optWeb3) {
     const web3 = optWeb3
-    extend(web3)
+    if (web3) extend(web3)
     return web3
   }