test: add missing error handling test for lock-utils

Add a unit test for `getCompletedAgents` in `src/lock-utils.mjs` to verify that:
1. It correctly identifies completed agents.
2. It handles `ENOENT` gracefully (silent).
3. It logs an error for non-`ENOENT` errors (e.g. permission denied).

The `getCompletedAgents` function already supported dependency injection via a `deps` object, which is utilized in this test to mock `fs.readdir` and other dependencies.

Co-authored-by: PR0M3TH3AN <[email protected]>

test/lock-utils.test.mjs

@@ -0,0 +1,84 @@
+import { describe, it, mock } from 'node:test';
+import assert from 'node:assert/strict';
+import { getCompletedAgents } from '../src/lock-utils.mjs';
+
+describe('lock-utils', () => {
+  describe('getCompletedAgents', () => {
+    // Helper to create deps
+    const createDeps = (overrides = {}) => ({
+      readdir: async () => [],
+      getDateStr: () => '2023-01-01',
+      getIsoWeek: () => '2023-W01',
+      ...overrides,
+    });
+
+    it('returns completed agents for daily cadence', async () => {
+      const deps = createDeps({
+        readdir: async () => [
+          '2023-01-01T10-00-00Z__agent1__completed.md',
+          '2023-01-01T11-00-00Z__agent2__failed.md',
+          '2023-01-02T10-00-00Z__agent3__completed.md', // different day
+        ],
+        getDateStr: () => '2023-01-01',
+      });
+      const result = await getCompletedAgents('daily', 'logs', deps);
+      assert.deepEqual([...result], ['agent1']);
+    });
+
+    it('returns completed agents for weekly cadence', async () => {
+      const deps = createDeps({
+        readdir: async () => [
+          '2023-01-01T10-00-00Z__agent1__completed.md', // Week 52 of 2022 (Sunday) - assuming mock logic
+          '2023-01-02T10-00-00Z__agent2__completed.md', // Week 01 of 2023 (Monday)
+        ],
+        getIsoWeek: (date) => {
+             if (!date) return '2023-W01'; // current week
+             if (date === '2023-01-01') return '2022-W52';
+             if (date === '2023-01-02') return '2023-W01';
+             return 'UNKNOWN';
+        }
+      });
+      // cadence is weekly
+      const result = await getCompletedAgents('weekly', 'logs', deps);
+      assert.deepEqual([...result], ['agent2']);
+    });
+
+    it('handles ENOENT gracefully', async () => {
+       const error = new Error('No such file or directory');
+       error.code = 'ENOENT';
+       const deps = createDeps({
+         readdir: async () => { throw error; }
+       });
+
+       // Spy on console.error to ensure it is NOT called
+       const consoleError = mock.method(console, 'error');
+
+       const result = await getCompletedAgents('daily', 'logs', deps);
+
+       assert.equal(consoleError.mock.callCount(), 0);
+       assert.deepEqual([...result], []);
+       consoleError.mock.restore();
+    });
+
+    it('logs error for non-ENOENT errors', async () => {
+       const error = new Error('Permission denied');
+       error.code = 'EACCES';
+       const deps = createDeps({
+         readdir: async () => { throw error; }
+       });
+
+       // Spy on console.error to verify it IS called
+       const consoleError = mock.method(console, 'error');
+
+       const result = await getCompletedAgents('daily', 'logs', deps);
+
+       assert.equal(consoleError.mock.callCount(), 1);
+       const call = consoleError.mock.calls[0];
+       assert.match(call.arguments[0], /Warning: Failed to read log dir/);
+       assert.match(call.arguments[0], /Permission denied/);
+
+       assert.deepEqual([...result], []);
+       consoleError.mock.restore();
+    });
+  });
+});