Consolidate MangaCircus app, scraper, and Compose baseline

scraper/test/json-file.test.js

@@ -0,0 +1,41 @@
+'use strict';
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs/promises');
+const os = require('node:os');
+const path = require('node:path');
+const { writeJsonAtomic } = require('../lib/json-file');
+
+test('Windows rename fallback replaces JSON without deleting the old state first', async t => {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), 'mc-json-'));
+  t.after(() => fs.rm(root, { recursive: true, force: true }));
+  const file = path.join(root, 'queue.json');
+  await fs.writeFile(file, '{"old":true}\n');
+  let failedOnce = false;
+  const io = { ...fs, async rename(from, to) {
+    if (to === file && !failedOnce) {
+      failedOnce = true;
+      const error = new Error('destination busy'); error.code = 'EEXIST'; throw error;
+    }
+    return fs.rename(from, to);
+  } };
+  await writeJsonAtomic(file, { next: true }, io);
+  assert.deepEqual(JSON.parse(await fs.readFile(file, 'utf8')), { next: true });
+  assert.deepEqual(await fs.readdir(root), ['queue.json']);
+});
+
+test('failed replacement restores the old JSON', async t => {
+  const root = await fs.mkdtemp(path.join(os.tmpdir(), 'mc-json-'));
+  t.after(() => fs.rm(root, { recursive: true, force: true }));
+  const file = path.join(root, 'queue.json');
+  await fs.writeFile(file, '{"old":true}\n');
+  const io = { ...fs, async rename(from, to) {
+    if (to === file && from.endsWith('.tmp')) {
+      const error = new Error('replacement blocked'); error.code = 'EEXIST'; throw error;
+    }
+    return fs.rename(from, to);
+  } };
+  await assert.rejects(writeJsonAtomic(file, { next: true }, io), /replacement blocked/);
+  assert.deepEqual(JSON.parse(await fs.readFile(file, 'utf8')), { old: true });
+  assert.deepEqual(await fs.readdir(root), ['queue.json']);
+});