diff --git a/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js b/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js
index 77ac67b1374..7618d9426d4 100644
--- a/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js
+++ b/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js
@@ -84,7 +84,7 @@ function zotVal(arbitrary, name, tag, count) {
 // prettier-ignore
 test('virtual object operations', t => {
   const log = [];
-  const { makeKind, flushCache, dumpStore } = makeFakeVirtualObjectManager(3, log);
+  const { makeKind, flushCache, dumpStore } = makeFakeVirtualObjectManager({ cacheSize: 3, log });
 
   const thingMaker = makeKind(makeThingInstance);
   const zotMaker = makeKind(makeZotInstance);
@@ -298,7 +298,9 @@ test('virtual object operations', t => {
 });
 
 test('weak store operations', t => {
-  const { makeWeakStore, makeKind } = makeFakeVirtualObjectManager(3);
+  const { makeWeakStore, makeKind } = makeFakeVirtualObjectManager({
+    cacheSize: 3,
+  });
 
   const thingMaker = makeKind(makeThingInstance);
   const zotMaker = makeKind(makeZotInstance);
@@ -346,7 +348,7 @@ test('virtualized weak collection operations', t => {
     VirtualObjectAwareWeakMap,
     VirtualObjectAwareWeakSet,
     makeKind,
-  } = makeFakeVirtualObjectManager(3);
+  } = makeFakeVirtualObjectManager({ cacheSize: 3 });
 
   const thingMaker = makeKind(makeThingInstance);
   const zotMaker = makeKind(makeZotInstance);
diff --git a/packages/SwingSet/test/virtualObjects/test-weakcollections.js b/packages/SwingSet/test/virtualObjects/test-weakcollections.js
index 2d8360a6298..5af91b0f91e 100644
--- a/packages/SwingSet/test/virtualObjects/test-weakcollections.js
+++ b/packages/SwingSet/test/virtualObjects/test-weakcollections.js
@@ -93,7 +93,7 @@ test('weakMap vref handling', async t => {
     VirtualObjectAwareWeakSet,
     valToSlot,
     slotToVal,
-  } = makeFakeVirtualObjectManager(3, log);
+  } = makeFakeVirtualObjectManager({ cacheSize: 3, log });
 
   function addCListEntry(slot, val) {
     slotToVal.set(slot, val);
diff --git a/packages/SwingSet/tools/fakeVirtualObjectManager.js b/packages/SwingSet/tools/fakeVirtualObjectManager.js
index 1b8126406f5..a35c586d69a 100644
--- a/packages/SwingSet/tools/fakeVirtualObjectManager.js
+++ b/packages/SwingSet/tools/fakeVirtualObjectManager.js
@@ -4,7 +4,8 @@ import { parseVatSlot } from '../src/parseVatSlots';
 
 import { makeVirtualObjectManager } from '../src/kernel/virtualObjectManager';
 
-export function makeFakeVirtualObjectManager(cacheSize = 100, log) {
+export function makeFakeVirtualObjectManager(options = {}) {
+  const { cacheSize = 100, log } = options;
   const fakeStore = new Map();
 
   function dumpStore() {
diff --git a/packages/SwingSet/tools/prepare-test-env.js b/packages/SwingSet/tools/prepare-test-env.js
index a588679fe93..f1adadf2709 100644
--- a/packages/SwingSet/tools/prepare-test-env.js
+++ b/packages/SwingSet/tools/prepare-test-env.js
@@ -9,7 +9,9 @@
 import './install-ses-debug';
 import { makeFakeVirtualObjectManager } from './fakeVirtualObjectManager';
 
-const { makeKind, makeWeakStore } = makeFakeVirtualObjectManager(3);
+const { makeKind, makeWeakStore } = makeFakeVirtualObjectManager({
+  cacheSize: 3,
+});
 
 globalThis.makeKind = makeKind;
 globalThis.makeWeakStore = makeWeakStore;