test: add unit tests for path_utils safe_join and safe_filename

tests/test_litellm/proxy/common_utils/test_path_utils.py

@@ -0,0 +1,46 @@
+import os
+
+import pytest
+
+from litellm.proxy.common_utils.path_utils import safe_filename, safe_join
+
+
+class TestSafeJoin:
+    def test_normal_path(self, tmp_path):
+        result = safe_join(str(tmp_path), "subdir", "file.yaml")
+        assert result == os.path.join(str(tmp_path), "subdir", "file.yaml")
+
+    def test_traversal_blocked(self, tmp_path):
+        with pytest.raises(ValueError, match="escapes base directory"):
+            safe_join(str(tmp_path), "../../etc/passwd.yaml")
+
+    def test_null_byte_blocked(self, tmp_path):
+        with pytest.raises(ValueError, match="null byte"):
+            safe_join(str(tmp_path), "file\x00.yaml")
+
+    def test_base_dir_itself(self, tmp_path):
+        result = safe_join(str(tmp_path))
+        assert result == str(tmp_path.resolve())
+
+
+class TestSafeFilename:
+    def test_normal_filename(self):
+        assert safe_filename("document.prompt") == "document.prompt"
+
+    def test_strips_unix_path(self):
+        assert safe_filename("../../etc/passwd.prompt") == "passwd.prompt"
+
+    def test_strips_windows_path(self):
+        assert safe_filename("..\\..\\etc\\passwd.prompt") == "passwd.prompt"
+
+    def test_null_byte_blocked(self):
+        with pytest.raises(ValueError, match="null byte"):
+            safe_filename("file\x00.prompt")
+
+    def test_dotdot_rejected(self):
+        with pytest.raises(ValueError, match="unsafe filename"):
+            safe_filename("..")
+
+    def test_empty_rejected(self):
+        with pytest.raises(ValueError):
+            safe_filename("")