fix(gateway): bound stdlib HTTP request work

tests/unit/test_gateway_bounded_http.py

@@ -0,0 +1,79 @@
+"""Unit tests for shared gateway stdlib HTTP resource boundaries."""
+# pylint: disable=protected-access
+
+from __future__ import annotations
+
+import io
+import socket
+import unittest
+
+from bot_bottle.gateway.bounded_http import (
+    BodyReadError,
+    BoundedThreadingHTTPServer,
+    read_declared_body,
+)
+
+
+class _Handler:
+    pass
+
+
+class _TimeoutStream:
+    def read(self, _size: int = -1, /) -> bytes:
+        raise TimeoutError
+
+
+class TestDeclaredBody(unittest.TestCase):
+    def setUp(self) -> None:
+        self.left, self.right = socket.socketpair()
+
+    def tearDown(self) -> None:
+        self.left.close()
+        self.right.close()
+
+    def test_rejects_incomplete_body(self) -> None:
+        with self.assertRaisesRegex(BodyReadError, "incomplete"):
+            read_declared_body(
+                io.BytesIO(b"short"),
+                self.left,
+                "10",
+                maximum=100,
+                timeout_seconds=1,
+                require_length=True,
+            )
+
+    def test_maps_read_timeout(self) -> None:
+        with self.assertRaises(BodyReadError) as caught:
+            read_declared_body(
+                _TimeoutStream(),
+                self.left,
+                "1",
+                maximum=100,
+                timeout_seconds=1,
+                require_length=True,
+            )
+        self.assertEqual(408, caught.exception.status)
+
+
+class TestBoundedServer(unittest.TestCase):
+    def test_saturated_server_rejects_without_spawning_thread(self) -> None:
+        client, peer = socket.socketpair()
+        with BoundedThreadingHTTPServer(
+            ("127.0.0.1", 0), _Handler, max_workers=1,  # type: ignore[arg-type]
+        ) as server:
+            with client, peer:
+                # Directly reserve the only slot to model an in-flight handler.
+                self.assertTrue(
+                    server._request_slots.acquire(  # pylint: disable=consider-using-with
+                        blocking=False,
+                    ),
+                )
+                try:
+                    server.process_request(client, ("127.0.0.1", 1))
+                    self.assertIn(b"503 Service Unavailable", peer.recv(1024))
+                finally:
+                    server._request_slots.release()
+
+
+if __name__ == "__main__":
+    unittest.main()