test(mcp): add output-max-size spec

Author: Skn0tt

tests/mcp/output-max-size.spec.ts

@@ -0,0 +1,60 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import fs from 'fs';
+import path from 'path';
+
+import { test, expect } from './fixtures';
+
+test('evicts oldest evictable files before write exceeds cap, pinned session.md survives', async ({ startClient, server }, testInfo) => {
+  const outputDir = testInfo.outputPath('output');
+  const { client } = await startClient({
+    config: {
+      outputDir,
+      saveSession: true,
+      outputMaxSize: 10_000,
+    },
+  });
+
+  await client.callTool({ name: 'browser_navigate', arguments: { url: server.HELLO_WORLD } });
+
+  for (let i = 0; i < 8; i++)
+    await client.callTool({ name: 'browser_take_screenshot' });
+  const pngs = fs.readdirSync(outputDir).filter(f => f.endsWith('.png'));
+  expect(pngs.length).toBeLessThan(8);
+  expect(pngs.reduce((acc, f) => acc + fs.statSync(path.join(outputDir, f)).size, 0)).toBeLessThanOrEqual(10_000);
+
+  const sessionFolder = fs.readdirSync(outputDir).find(e => e.startsWith('session-'));
+  expect(sessionFolder).toBeTruthy();
+  expect(fs.existsSync(path.join(outputDir, sessionFolder!, 'session.md'))).toBe(true);
+});
+
+test('oversize single file evicts everything and still writes', async ({ startClient, server }, testInfo) => {
+  const outputDir = testInfo.outputPath('output');
+  const { client } = await startClient({
+    config: {
+      outputDir,
+      outputMaxSize: 100,
+    },
+  });
+
+  await client.callTool({ name: 'browser_navigate', arguments: { url: server.HELLO_WORLD } });
+
+  await client.callTool({ name: 'browser_take_screenshot' });
+  await client.callTool({ name: 'browser_take_screenshot' });
+
+  expect(fs.readdirSync(outputDir)).toHaveLength(1);
+});