test(vow): add fake liveslots upgrade test

packages/vow/package.json

@@ -30,6 +30,8 @@
   },
   "devDependencies": {
     "@agoric/internal": "^0.3.2",
+    "@agoric/swingset-vat": "^0.32.2",
+    "@agoric/zone": "^0.2.2",
     "@endo/far": "^1.1.5",
     "@endo/init": "^1.1.4",
     "ava": "^5.3.0",

packages/vow/test/watch-upgrade.test.js

@@ -0,0 +1,65 @@
+import {
+  annihilate,
+  startLife,
+  test,
+} from '@agoric/swingset-vat/tools/prepare-strict-test-env-ava.js';
+
+import { makeDurableZone } from '@agoric/zone/durable.js';
+
+import { prepareVowTools } from '../vat.js';
+
+test.serial('vow resolve across upgrade', async t => {
+  annihilate();
+
+  t.plan(1);
+
+  await startLife(async baggage => {
+    const zone = makeDurableZone(baggage, 'durableRoot');
+    const vowTools = prepareVowTools(zone);
+    const watcher = zone.exo('DurableVowTestWatcher', undefined, {
+      onFulfilled(value) {
+        t.fail(
+          `First incarnation watcher onFulfilled triggered with value ${value}`,
+        );
+      },
+      onRejected(reason) {
+        t.fail(
+          `First incarnation watcher onRejected triggered with reason ${reason}`,
+        );
+      },
+    });
+
+    const testVowKit = zone.makeOnce('testVowKit', () => vowTools.makeVowKit());
+
+    vowTools.watch(testVowKit.vow, watcher);
+  });
+
+  await startLife(
+    baggage => {
+      const zone = makeDurableZone(baggage, 'durableRoot');
+      prepareVowTools(zone);
+      // We're only preparing the watcher exo with new behavior. The instance is
+      // already attached as a watcher for the test vow
+      zone.exo('DurableVowTestWatcher', undefined, {
+        onFulfilled(value) {
+          t.is(value, 42, 'vow resolved with value 42');
+        },
+        onRejected(reason) {
+          t.fail(
+            `Second incarnation watcher onRejected triggered with reason ${reason}`,
+          );
+        },
+      });
+
+      /** @type {import('../src/types.js').VowResolver} */
+      const testVowKitResolver = zone.makeOnce('testVowKit', () => {
+        t.fail('testVowKit maker called');
+      }).resolver;
+
+      return { testVowKitResolver };
+    },
+    async ({ testVowKitResolver }) => {
+      testVowKitResolver.resolve(42);
+    },
+  );
+});