add test for web browser engine

tests/conftest.py

@@ -11,6 +11,8 @@ import pytest
 from metagpt.logs import logger
 
 from metagpt.provider.openai_api import OpenAIGPTAPI as GPTAPI
+import asyncio
+import re
 
 
 class Context:
@@ -36,4 +38,32 @@ def llm_api():
 @pytest.fixture(scope="function")
 def mock_llm():
     # Create a mock LLM for testing
-    return Mock()
+    return Mock()
+
+
+@pytest.fixture(scope="session")
+def proxy():
+    pattern = re.compile(
+        rb"(?P<method>[a-zA-Z]+) (?P<uri>(\w+://)?(?P<host>[^\s\'\"<>\[\]{}|/:]+)(:(?P<port>\d+))?[^\s\'\"<>\[\]{}|]*) "
+    )
+
+    async def pipe(reader, writer):
+        while not reader.at_eof():
+            writer.write(await reader.read(2048))
+        writer.close()
+
+    async def handle_client(reader, writer):
+        data = await reader.readuntil(b"\r\n\r\n")
+        print(f"Proxy: {data}")  # checking with capfd fixture
+        infos = pattern.match(data)
+        host, port = infos.group("host"), infos.group("port")
+        port = int(port) if port else 80
+        remote_reader, remote_writer = await asyncio.open_connection(host, port)
+        if data.startswith(b"CONNECT"):
+            writer.write(b"HTTP/1.1 200 Connection Established\r\n\r\n")
+        else:
+            remote_writer.write(data)
+        await asyncio.gather(pipe(reader, remote_writer), pipe(remote_reader, writer))
+
+    server = asyncio.get_event_loop().run_until_complete(asyncio.start_server(handle_client, "127.0.0.1", 0))
+    return "http://{}:{}".format(*server.sockets[0].getsockname())