diff --git a/src/flows/channel-setup.test.ts b/src/flows/channel-setup.test.ts
index 0d1fe0dbb0f..891fecf2731 100644
--- a/src/flows/channel-setup.test.ts
+++ b/src/flows/channel-setup.test.ts
@@ -79,7 +79,7 @@ function makePluginRegistry(overrides: Partial<PluginRegistry> = {}): PluginRegi
 }
 
 function callArg<T>(mock: { mock: { calls: unknown[][] } }, index = 0, _type?: (value: T) => T): T {
-  const call = mock.mock.calls.at(index);
+  const call = mock.mock.calls[index];
   if (!call) {
     throw new Error(`Expected mock call ${index}`);
   }
@@ -87,7 +87,7 @@ function callArg<T>(mock: { mock: { calls: unknown[][] } }, index = 0, _type?: (
 }
 
 function mockCall(mock: { mock: { calls: unknown[][] } }, index = 0): unknown[] {
-  const call = mock.mock.calls.at(index);
+  const call = mock.mock.calls[index];
   if (!call) {
     throw new Error(`Expected mock call ${index}`);
   }