chore: 添加虚拟环境到仓库

- 添加 backend_service/venv 虚拟环境
- 包含所有Python依赖包
- 注意：虚拟环境约393MB，包含12655个文件

backend_service/venv/lib/python3.13/site-packages/fsspec/conftest.py

@@ -0,0 +1,125 @@
+import os
+import shutil
+import subprocess
+import sys
+import time
+from collections import deque
+from collections.abc import Generator, Sequence
+
+import pytest
+
+import fsspec
+
+
+@pytest.fixture()
+def m():
+    """
+    Fixture providing a memory filesystem.
+    """
+    m = fsspec.filesystem("memory")
+    m.store.clear()
+    m.pseudo_dirs.clear()
+    m.pseudo_dirs.append("")
+    try:
+        yield m
+    finally:
+        m.store.clear()
+        m.pseudo_dirs.clear()
+        m.pseudo_dirs.append("")
+
+
+class InstanceCacheInspector:
+    """
+    Helper class to inspect instance caches of filesystem classes in tests.
+    """
+
+    def clear(self) -> None:
+        """
+        Clear instance caches of all currently imported filesystem classes.
+        """
+        classes = deque([fsspec.spec.AbstractFileSystem])
+        while classes:
+            cls = classes.popleft()
+            cls.clear_instance_cache()
+            classes.extend(cls.__subclasses__())
+
+    def gather_counts(self, *, omit_zero: bool = True) -> dict[str, int]:
+        """
+        Gather counts of filesystem instances in the instance caches
+        of all currently imported filesystem classes.
+
+        Parameters
+        ----------
+        omit_zero:
+            Whether to omit instance types with no cached instances.
+        """
+        out: dict[str, int] = {}
+        classes = deque([fsspec.spec.AbstractFileSystem])
+        while classes:
+            cls = classes.popleft()
+            count = len(cls._cache)  # there is no public interface for the cache
+            # note: skip intermediate AbstractFileSystem subclasses
+            #   if they proxy the protocol attribute via a property.
+            if isinstance(cls.protocol, (Sequence, str)):
+                key = cls.protocol if isinstance(cls.protocol, str) else cls.protocol[0]
+                if count or not omit_zero:
+                    out[key] = count
+            classes.extend(cls.__subclasses__())
+        return out
+
+
+@pytest.fixture(scope="function", autouse=True)
+def instance_caches() -> Generator[InstanceCacheInspector, None, None]:
+    """
+    Fixture to ensure empty filesystem instance caches before and after a test.
+
+    Used by default for all tests.
+    Clears caches of all imported filesystem classes.
+    Can be used to write test assertions about instance caches.
+
+    Usage:
+
+        def test_something(instance_caches):
+            # Test code here
+            fsspec.open("file://abc")
+            fsspec.open("memory://foo/bar")
+
+            # Test assertion
+            assert instance_caches.gather_counts() == {"file": 1, "memory": 1}
+
+    Returns
+    -------
+    instance_caches: An instance cache inspector for clearing and inspecting caches.
+    """
+    ic = InstanceCacheInspector()
+
+    ic.clear()
+    try:
+        yield ic
+    finally:
+        ic.clear()
+
+
+@pytest.fixture(scope="function")
+def ftp_writable(tmpdir):
+    """
+    Fixture providing a writable FTP filesystem.
+    """
+    pytest.importorskip("pyftpdlib")
+
+    d = str(tmpdir)
+    with open(os.path.join(d, "out"), "wb") as f:
+        f.write(b"hello" * 10000)
+    P = subprocess.Popen(
+        [sys.executable, "-m", "pyftpdlib", "-d", d, "-u", "user", "-P", "pass", "-w"]
+    )
+    try:
+        time.sleep(1)
+        yield "localhost", 2121, "user", "pass"
+    finally:
+        P.terminate()
+        P.wait()
+        try:
+            shutil.rmtree(tmpdir)
+        except Exception:
+            pass