test(proxy): cover every /v1/files route error type and param

tests/test_litellm/proxy/openai_files_endpoint/test_files_endpoint.py

@@ -4666,3 +4666,102 @@ def test_create_file_path_traversal_filename_rejected_before_forwarding(monkeypa
     assert error["param"] == "file"
     assert "traversal" in error["message"].lower()
     assert forwarded_calls == []
+
+
+def _setup_managed_file_route_answering_404(mocker: MockerFixture, monkeypatch, llm_router: Router):
+    """Wire the single-file routes to a managed file store that knows no file, the way the
+    managed files hook answers once a file has been deleted or was never the caller's."""
+    import litellm.proxy.proxy_server as ps
+    from fastapi import HTTPException
+    from litellm.llms.base_llm.files.transformation import BaseFileEndpoints
+    from litellm.proxy._types import LitellmUserRoles
+
+    async def _file_not_found(file_id: str, **kwargs):
+        raise HTTPException(status_code=404, detail=f"File not found: {file_id}")
+
+    proxy_logging_obj = setup_proxy_logging_object(monkeypatch, llm_router)
+    managed_files = mocker.MagicMock(spec=BaseFileEndpoints)
+    managed_files.afile_retrieve = mocker.AsyncMock(side_effect=_file_not_found)
+    managed_files.afile_delete = mocker.AsyncMock(side_effect=_file_not_found)
+    managed_files.afile_content = mocker.AsyncMock(side_effect=_file_not_found)
+    proxy_logging_obj.proxy_hook_mapping["managed_files"] = managed_files
+    monkeypatch.setattr("litellm.proxy.proxy_server.llm_router", llm_router)
+
+    app.dependency_overrides[ps.user_api_key_auth] = lambda: UserAPIKeyAuth(
+        api_key="test-key",
+        user_role=LitellmUserRoles.INTERNAL_USER,
+        user_id="test-user",
+    )
+
+
+def _call_managed_file_route(method: str, path: str):
+    try:
+        return client.request(method, path, headers={"Authorization": "Bearer test-key"})
+    finally:
+        import litellm.proxy.proxy_server as ps
+
+        app.dependency_overrides.pop(ps.user_api_key_auth, None)
+
+
+def _missing_managed_file_error(file_id: str) -> dict:
+    return {
+        "error": {
+            "message": f"File not found: {file_id}",
+            "type": "invalid_request_error",
+            "param": None,
+            "code": "404",
+        }
+    }
+
+
+def test_create_file_reports_a_half_specified_expires_after_as_a_400(monkeypatch, llm_router: Router):
+    """A 400 raised inside the route answers with the type a 400 stands for and a JSON null
+    param, not the literal string "None" in both fields, so a client can classify it."""
+    setup_proxy_logging_object(monkeypatch, llm_router)
+    monkeypatch.setattr("litellm.proxy.proxy_server.llm_router", llm_router)
+
+    response = client.post(
+        "/v1/files",
+        files={"file": ("mydata.jsonl", VALID_BATCH_LINE, "application/jsonl")},
+        data={"purpose": "batch", "target_model_names": "gpt-3.5-turbo", "expires_after[anchor]": "created_at"},
+        headers={"Authorization": "Bearer test-key"},
+    )
+
+    assert response.status_code == 400, response.text
+    error = response.json()["error"]
+    assert "expires_after[seconds]" in error["message"]
+    assert error["type"] == "invalid_request_error"
+    assert error["param"] is None
+    assert error["code"] == "400"
+
+
+def test_get_file_reports_a_missing_managed_file_as_a_404(mocker: MockerFixture, monkeypatch, llm_router: Router):
+    _setup_managed_file_route_answering_404(mocker, monkeypatch, llm_router)
+    file_id = _unified_managed_file_id()
+
+    response = _call_managed_file_route("GET", f"/v1/files/{file_id}")
+
+    assert response.status_code == 404, response.text
+    assert response.json() == _missing_managed_file_error(file_id)
+
+
+def test_delete_file_reports_a_missing_managed_file_as_a_404(mocker: MockerFixture, monkeypatch, llm_router: Router):
+    _setup_managed_file_route_answering_404(mocker, monkeypatch, llm_router)
+    file_id = _unified_managed_file_id()
+
+    response = _call_managed_file_route("DELETE", f"/v1/files/{file_id}")
+
+    assert response.status_code == 404, response.text
+    assert response.json() == _missing_managed_file_error(file_id)
+
+
+def test_get_file_content_reports_a_missing_managed_file_as_a_404(
+    mocker: MockerFixture, monkeypatch, llm_router: Router
+):
+    _setup_managed_file_route_answering_404(mocker, monkeypatch, llm_router)
+    file_id = _unified_managed_file_id()
+
+    response = _call_managed_file_route("GET", f"/v1/files/{file_id}/content")
+
+    assert response.status_code == 404, response.text
+    assert response.json() == _missing_managed_file_error(file_id)