feat(animetosho): add English/Japanese subtitle download integration (#159)

src/animetosho/fetch-limits.test.ts

@@ -0,0 +1,119 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import * as http from 'node:http';
+import type { AddressInfo } from 'node:net';
+
+import { animetoshoFetchJson } from './utils.js';
+
+interface TestServer {
+  baseUrl: string;
+  close: () => Promise<void>;
+}
+
+function startServer(handler: http.RequestListener): Promise<TestServer> {
+  return new Promise((resolve) => {
+    const server = http.createServer(handler);
+    server.listen(0, '127.0.0.1', () => {
+      const { port } = server.address() as AddressInfo;
+      resolve({
+        baseUrl: `http://127.0.0.1:${port}`,
+        close: () =>
+          new Promise((done) => {
+            server.closeAllConnections?.();
+            server.close(() => done());
+          }),
+      });
+    });
+  });
+}
+
+test('animetoshoFetchJson gives up on a hanging response', async () => {
+  const server = await startServer((_req, res) => {
+    res.writeHead(200, { 'Content-Type': 'application/json' });
+    // Never end the response.
+    res.write('[');
+  });
+
+  try {
+    const result = await animetoshoFetchJson(
+      '/json',
+      {},
+      { baseUrl: server.baseUrl, timeoutMs: 150 },
+    );
+    assert.equal(result.ok, false);
+    if (!result.ok) {
+      assert.match(result.error.error, /timed out/i);
+    }
+  } finally {
+    await server.close();
+  }
+});
+
+test('animetoshoFetchJson rejects an oversized response', async () => {
+  const server = await startServer((_req, res) => {
+    res.writeHead(200, { 'Content-Type': 'application/json' });
+    res.end(JSON.stringify(Array.from({ length: 2000 }, (_, index) => ({ id: index }))));
+  });
+
+  try {
+    const result = await animetoshoFetchJson(
+      '/json',
+      {},
+      { baseUrl: server.baseUrl, maxResponseBytes: 512 },
+    );
+    assert.equal(result.ok, false);
+    if (!result.ok) {
+      assert.match(result.error.error, /too large/i);
+    }
+  } finally {
+    await server.close();
+  }
+});
+
+test('animetoshoFetchJson decodes multi-byte characters split across chunks', async () => {
+  const title = '葬送のフリーレン';
+  const body = Buffer.from(JSON.stringify([{ id: 1, title }]), 'utf8');
+  // Split inside the first Japanese character's 3-byte UTF-8 sequence.
+  const splitAt = body.indexOf(Buffer.from(title, 'utf8')) + 1;
+
+  const server = await startServer((_req, res) => {
+    res.writeHead(200, { 'Content-Type': 'application/json' });
+    res.write(body.subarray(0, splitAt));
+    setTimeout(() => res.end(body.subarray(splitAt)), 10);
+  });
+
+  try {
+    const result = await animetoshoFetchJson<Array<{ id: number; title: string }>>(
+      '/json',
+      {},
+      { baseUrl: server.baseUrl },
+    );
+    assert.equal(result.ok, true);
+    if (result.ok) {
+      assert.equal(result.data[0]!.title, title);
+    }
+  } finally {
+    await server.close();
+  }
+});
+
+test('animetoshoFetchJson still parses a normal response', async () => {
+  const server = await startServer((_req, res) => {
+    res.writeHead(200, { 'Content-Type': 'application/json' });
+    res.end(JSON.stringify([{ id: 1, title: 'ok' }]));
+  });
+
+  try {
+    const result = await animetoshoFetchJson<Array<{ id: number }>>(
+      '/json',
+      { q: 'x' },
+      { baseUrl: server.baseUrl },
+    );
+    assert.equal(result.ok, true);
+    if (result.ok) {
+      assert.deepEqual(result.data, [{ id: 1, title: 'ok' }]);
+    }
+  } finally {
+    await server.close();
+  }
+});