Make journal write failure test deterministic

test/server/activity-journal-service.test.js

@@ -107,10 +107,13 @@ test('corrupt journal is isolated and recovery becomes a safe event', (t) => {
 
 test('journal exposes a latched write failure until a later append succeeds', (t) => {
   const filePath = fixture(t);
-  const directory = path.dirname(filePath);
   const service = createActivityJournalService({ filePath });
   service.append(event('before-error'));
-  fs.chmodSync(directory, 0o555);
+  const renameSync = fs.renameSync;
+  fs.renameSync = (source, target) => {
+    if (target === filePath) throw new Error('simulated journal write failure');
+    return renameSync(source, target);
+  };
   try {
     assert.throws(() => service.append(event('lost')));
     const failed = service.page();
@@ -119,7 +122,7 @@ test('journal exposes a latched write failure until a later append succeeds', (t
     assert.equal(failed.events.length, 1);
     assert.equal(failed.events[0].dedupeKey, null);
   } finally {
-    fs.chmodSync(directory, 0o755);
+    fs.renameSync = renameSync;
   }
   service.append(event('recovered'));
   assert.equal(service.page().storage.status, 'ready');