Implement a mock virtual object manager to support unit tests outside SwingSet

packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js

@@ -1,80 +1,13 @@
 import '@agoric/install-ses';
 import test from 'ava';
-import { makeMarshal, Far } from '@agoric/marshal';
-import { assert } from '@agoric/assert';
-import { parseVatSlot } from '../../src/parseVatSlots';
-import { makeVirtualObjectManager } from '../../src/kernel/virtualObjectManager';
+import { Far } from '@agoric/marshal';
+import { makeFakeVirtualObjectManager } from '../../tools/fakeVirtualObjectManager';
 
 function capdata(body, slots = []) {
   return harden({ body, slots });
 }
 const s = JSON.stringify;
 
-function makeAllTheStuff(cacheSize) {
-  const fakeStore = new Map();
-
-  function dumpStore() {
-    const result = [];
-    for (const entry of fakeStore.entries()) {
-      result.push(entry);
-    }
-    result.sort((e1, e2) => e1[0].localeCompare(e2[0]));
-    return result;
-  }
-
-  const fakeSyscall = {
-    vatstoreGet: key => fakeStore.get(key),
-    vatstoreSet: (key, value) => fakeStore.set(key, value),
-    vatstoreDelete: key => fakeStore.delete(key),
-  };
-
-  let nextExportID = 1;
-  function fakeAllocateExportID() {
-    const exportID = nextExportID;
-    nextExportID += 1;
-    return exportID;
-  }
-
-  const valToSlot = new WeakMap();
-
-  // eslint-disable-next-line no-use-before-define
-  const fakeMarshal = makeMarshal(fakeConvertValToSlot, fakeConvertSlotToVal);
-
-  const {
-    makeVirtualObjectRepresentative,
-    makeWeakStore,
-    makeKind,
-    flushCache,
-  } = makeVirtualObjectManager(
-    fakeSyscall,
-    fakeAllocateExportID,
-    valToSlot,
-    fakeMarshal,
-    cacheSize,
-  );
-
-  function fakeConvertValToSlot(val) {
-    return valToSlot.get(val);
-  }
-
-  function fakeConvertSlotToVal(slot) {
-    const { type, virtual } = parseVatSlot(slot);
-    assert(
-      virtual,
-      'fakeConvertSlotToVal only works with virtual object references',
-    );
-    assert.equal(type, 'object');
-    return makeVirtualObjectRepresentative(slot);
-  }
-
-  return {
-    makeWeakStore,
-    makeKind,
-    flushCache,
-    dumpStore,
-  };
-}
-
 function makeThingInstance(state) {
   return {
     init(label = 'thing', counter = 0) {
@@ -132,7 +65,7 @@ function makeZotInstance(state) {
 }
 
 test('virtual object operations', t => {
-  const { makeKind, flushCache, dumpStore } = makeAllTheStuff(3);
+  const { makeKind, flushCache, dumpStore } = makeFakeVirtualObjectManager(3);
 
   const thingMaker = makeKind(makeThingInstance);
   const zotMaker = makeKind(makeZotInstance);
@@ -231,7 +164,7 @@ test('virtual object operations', t => {
 });
 
 test('weak store operations', t => {
-  const { makeWeakStore, makeKind } = makeAllTheStuff(3);
+  const { makeWeakStore, makeKind } = makeFakeVirtualObjectManager(3);
 
   const thingMaker = makeKind(makeThingInstance);
   const zotMaker = makeKind(makeZotInstance);

packages/SwingSet/tools/fakeVirtualObjectManager.js

@@ -0,0 +1,77 @@
+import { makeMarshal } from '@agoric/marshal';
+import { assert } from '@agoric/assert';
+import { parseVatSlot } from '../src/parseVatSlots';
+
+import { makeVirtualObjectManager } from '../src/kernel/virtualObjectManager';
+
+export function makeFakeVirtualObjectManager(cacheSize = 100) {
+  const fakeStore = new Map();
+
+  function dumpStore() {
+    const result = [];
+    for (const entry of fakeStore.entries()) {
+      result.push(entry);
+    }
+    result.sort((e1, e2) => e1[0].localeCompare(e2[0]));
+    return result;
+  }
+
+  const fakeSyscall = {
+    vatstoreGet: key => fakeStore.get(key),
+    vatstoreSet: (key, value) => fakeStore.set(key, value),
+    vatstoreDelete: key => fakeStore.delete(key),
+  };
+
+  let nextExportID = 1;
+  function fakeAllocateExportID() {
+    const exportID = nextExportID;
+    nextExportID += 1;
+    return exportID;
+  }
+
+  const valToSlot = new WeakMap();
+  const slotToVal = new Map();
+
+  function fakeConvertValToSlot(val) {
+    if (!valToSlot.has(val)) {
+      const slot = `o+${fakeAllocateExportID()}`;
+      valToSlot.set(val, slot);
+      slotToVal.set(slot, val);
+    }
+    return valToSlot.get(val);
+  }
+
+  function fakeConvertSlotToVal(slot) {
+    const { type, virtual } = parseVatSlot(slot);
+    assert.equal(type, 'object');
+    if (virtual) {
+      // eslint-disable-next-line no-use-before-define
+      return makeVirtualObjectRepresentative(slot);
+    } else {
+      return slotToVal.get(slot);
+    }
+  }
+
+  // eslint-disable-next-line no-use-before-define
+  const fakeMarshal = makeMarshal(fakeConvertValToSlot, fakeConvertSlotToVal);
+
+  const {
+    makeVirtualObjectRepresentative,
+    makeWeakStore,
+    makeKind,
+    flushCache,
+  } = makeVirtualObjectManager(
+    fakeSyscall,
+    fakeAllocateExportID,
+    valToSlot,
+    fakeMarshal,
+    cacheSize,
+  );
+
+  return {
+    makeKind,
+    makeWeakStore,
+    flushCache,
+    dumpStore,
+  };
+}