tests: improve RAGFlow coverage based on Codecov report (#13219)

### What problem does this PR solve?

Codecov’s coverage report shows that several RAGFlow code paths are
currently untested or under-tested. This makes it easier for regressions
to slip in during refactors and feature work.
This PR adds targeted automated tests to cover the files and branches
highlighted by Codecov, improving confidence in core behavior while
keeping runtime functionality unchanged.

### Type of change

- [x] Other (please describe): Test coverage improvement (adds/extends
unit and integration tests to address Codecov-reported gaps)

test/testcases/test_web_api/test_file_app/test_file2document_routes_unit.py

@@ -0,0 +1,367 @@
+#
+#  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+import asyncio
+import functools
+import importlib.util
+import sys
+from copy import deepcopy
+from enum import Enum
+from pathlib import Path
+from types import ModuleType, SimpleNamespace
+
+import pytest
+
+
+class _DummyManager:
+    def route(self, *_args, **_kwargs):
+        def decorator(func):
+            return func
+
+        return decorator
+
+
+class _AwaitableValue:
+    def __init__(self, value):
+        self._value = value
+
+    def __await__(self):
+        async def _co():
+            return self._value
+
+        return _co().__await__()
+
+
+class _DummyFile:
+    def __init__(self, file_id, file_type, *, name="file.txt", location="loc", size=1):
+        self.id = file_id
+        self.type = file_type
+        self.name = name
+        self.location = location
+        self.size = size
+
+
+class _FalsyFile(_DummyFile):
+    def __bool__(self):
+        return False
+
+
+def _run(coro):
+    return asyncio.run(coro)
+
+
+def _set_request_json(monkeypatch, module, payload_state):
+    async def _req_json():
+        return deepcopy(payload_state)
+
+    monkeypatch.setattr(module, "get_request_json", _req_json)
+
+
+@pytest.fixture(scope="session")
+def auth():
+    return "unit-auth"
+
+
+@pytest.fixture(scope="session", autouse=True)
+def set_tenant_info():
+    return None
+
+
+def _load_file2document_module(monkeypatch):
+    repo_root = Path(__file__).resolve().parents[4]
+
+    api_pkg = ModuleType("api")
+    api_pkg.__path__ = [str(repo_root / "api")]
+    monkeypatch.setitem(sys.modules, "api", api_pkg)
+
+    apps_mod = ModuleType("api.apps")
+    apps_mod.__path__ = [str(repo_root / "api" / "apps")]
+    apps_mod.current_user = SimpleNamespace(id="user-1")
+    apps_mod.login_required = lambda func: func
+    monkeypatch.setitem(sys.modules, "api.apps", apps_mod)
+    api_pkg.apps = apps_mod
+
+    db_pkg = ModuleType("api.db")
+    db_pkg.__path__ = []
+
+    class _FileType(Enum):
+        FOLDER = "folder"
+        DOC = "doc"
+
+    db_pkg.FileType = _FileType
+    monkeypatch.setitem(sys.modules, "api.db", db_pkg)
+    api_pkg.db = db_pkg
+
+    services_pkg = ModuleType("api.db.services")
+    services_pkg.__path__ = []
+    monkeypatch.setitem(sys.modules, "api.db.services", services_pkg)
+
+    file2document_mod = ModuleType("api.db.services.file2document_service")
+
+    class _StubFile2DocumentService:
+        @staticmethod
+        def get_by_file_id(_file_id):
+            return []
+
+        @staticmethod
+        def delete_by_file_id(*_args, **_kwargs):
+            return None
+
+        @staticmethod
+        def insert(_payload):
+            return SimpleNamespace(to_json=lambda: {})
+
+    file2document_mod.File2DocumentService = _StubFile2DocumentService
+    monkeypatch.setitem(sys.modules, "api.db.services.file2document_service", file2document_mod)
+    services_pkg.file2document_service = file2document_mod
+
+    file_service_mod = ModuleType("api.db.services.file_service")
+
+    class _StubFileService:
+        @staticmethod
+        def get_by_ids(_file_ids):
+            return []
+
+        @staticmethod
+        def get_all_innermost_file_ids(_file_id, _acc):
+            return []
+
+        @staticmethod
+        def get_by_id(_file_id):
+            return True, _DummyFile(_file_id, _FileType.DOC.value)
+
+    file_service_mod.FileService = _StubFileService
+    monkeypatch.setitem(sys.modules, "api.db.services.file_service", file_service_mod)
+    services_pkg.file_service = file_service_mod
+
+    kb_service_mod = ModuleType("api.db.services.knowledgebase_service")
+
+    class _StubKnowledgebaseService:
+        @staticmethod
+        def get_by_id(_kb_id):
+            return False, None
+
+    kb_service_mod.KnowledgebaseService = _StubKnowledgebaseService
+    monkeypatch.setitem(sys.modules, "api.db.services.knowledgebase_service", kb_service_mod)
+    services_pkg.knowledgebase_service = kb_service_mod
+
+    document_service_mod = ModuleType("api.db.services.document_service")
+
+    class _StubDocumentService:
+        @staticmethod
+        def get_by_id(doc_id):
+            return True, SimpleNamespace(id=doc_id)
+
+        @staticmethod
+        def get_tenant_id(_doc_id):
+            return "tenant-1"
+
+        @staticmethod
+        def remove_document(*_args, **_kwargs):
+            return True
+
+        @staticmethod
+        def insert(_payload):
+            return SimpleNamespace(id="doc-1")
+
+    document_service_mod.DocumentService = _StubDocumentService
+    monkeypatch.setitem(sys.modules, "api.db.services.document_service", document_service_mod)
+    services_pkg.document_service = document_service_mod
+
+    api_utils_mod = ModuleType("api.utils.api_utils")
+
+    def get_json_result(data=None, message="", code=0):
+        return {"code": code, "data": data, "message": message}
+
+    def get_data_error_result(message=""):
+        return {"code": 102, "data": None, "message": message}
+
+    async def get_request_json():
+        return {}
+
+    def server_error_response(err):
+        return {"code": 500, "data": None, "message": str(err)}
+
+    def validate_request(*_keys):
+        def _decorator(func):
+            @functools.wraps(func)
+            async def _wrapper(*args, **kwargs):
+                return await func(*args, **kwargs)
+
+            return _wrapper
+
+        return _decorator
+
+    api_utils_mod.get_json_result = get_json_result
+    api_utils_mod.get_data_error_result = get_data_error_result
+    api_utils_mod.get_request_json = get_request_json
+    api_utils_mod.server_error_response = server_error_response
+    api_utils_mod.validate_request = validate_request
+    monkeypatch.setitem(sys.modules, "api.utils.api_utils", api_utils_mod)
+
+    misc_utils_mod = ModuleType("common.misc_utils")
+    misc_utils_mod.get_uuid = lambda: "uuid"
+    monkeypatch.setitem(sys.modules, "common.misc_utils", misc_utils_mod)
+
+    constants_mod = ModuleType("common.constants")
+
+    class _RetCode:
+        ARGUMENT_ERROR = 101
+
+    constants_mod.RetCode = _RetCode
+    monkeypatch.setitem(sys.modules, "common.constants", constants_mod)
+
+    module_name = "test_file2document_routes_unit_module"
+    module_path = repo_root / "api" / "apps" / "file2document_app.py"
+    spec = importlib.util.spec_from_file_location(module_name, module_path)
+    module = importlib.util.module_from_spec(spec)
+    module.manager = _DummyManager()
+    monkeypatch.setitem(sys.modules, module_name, module)
+    spec.loader.exec_module(module)
+    return module
+
+
+@pytest.mark.p2
+def test_convert_branch_matrix_unit(monkeypatch):
+    module = _load_file2document_module(monkeypatch)
+    req_state = {"kb_ids": ["kb-1"], "file_ids": ["f1"]}
+    _set_request_json(monkeypatch, module, req_state)
+
+    events = {"deleted": []}
+
+    monkeypatch.setattr(module.FileService, "get_by_ids", lambda _ids: [_FalsyFile("f1", module.FileType.DOC.value)])
+    res = _run(module.convert())
+    assert res["message"] == "File not found!"
+
+    monkeypatch.setattr(module.FileService, "get_by_ids", lambda _ids: [_DummyFile("f1", module.FileType.DOC.value)])
+    monkeypatch.setattr(module.File2DocumentService, "get_by_file_id", lambda _file_id: [SimpleNamespace(document_id="doc-1")])
+    monkeypatch.setattr(module.DocumentService, "get_by_id", lambda _doc_id: (False, None))
+    res = _run(module.convert())
+    assert res["message"] == "Document not found!"
+
+    monkeypatch.setattr(module.DocumentService, "get_by_id", lambda _doc_id: (True, SimpleNamespace(id=_doc_id)))
+    monkeypatch.setattr(module.DocumentService, "get_tenant_id", lambda _doc_id: None)
+    res = _run(module.convert())
+    assert res["message"] == "Tenant not found!"
+
+    monkeypatch.setattr(module.DocumentService, "get_tenant_id", lambda _doc_id: "tenant-1")
+    monkeypatch.setattr(module.DocumentService, "remove_document", lambda *_args, **_kwargs: False)
+    res = _run(module.convert())
+    assert "Document removal" in res["message"]
+
+    monkeypatch.setattr(module.DocumentService, "remove_document", lambda *_args, **_kwargs: True)
+    monkeypatch.setattr(module.File2DocumentService, "get_by_file_id", lambda _file_id: [])
+    monkeypatch.setattr(module.File2DocumentService, "delete_by_file_id", lambda file_id: events["deleted"].append(file_id))
+    monkeypatch.setattr(module.KnowledgebaseService, "get_by_id", lambda _kb_id: (False, None))
+    res = _run(module.convert())
+    assert res["message"] == "Can't find this dataset!"
+    assert events["deleted"] == ["f1"]
+
+    kb = SimpleNamespace(id="kb-1", parser_id="naive", pipeline_id="p1", parser_config={})
+    monkeypatch.setattr(module.KnowledgebaseService, "get_by_id", lambda _kb_id: (True, kb))
+    monkeypatch.setattr(module.FileService, "get_by_id", lambda _file_id: (False, None))
+    res = _run(module.convert())
+    assert res["message"] == "Can't find this file!"
+
+    req_state["file_ids"] = ["folder-1"]
+    monkeypatch.setattr(module.FileService, "get_by_ids", lambda _ids: [_DummyFile("folder-1", module.FileType.FOLDER.value, name="folder")])
+    monkeypatch.setattr(module.FileService, "get_all_innermost_file_ids", lambda _file_id, _acc: ["inner-1"])
+    monkeypatch.setattr(
+        module.FileService,
+        "get_by_id",
+        lambda _file_id: (True, _DummyFile("inner-1", module.FileType.DOC.value, name="inner.txt", location="inner.loc", size=2)),
+    )
+    monkeypatch.setattr(module.DocumentService, "insert", lambda _payload: SimpleNamespace(id="doc-new"))
+    monkeypatch.setattr(
+        module.File2DocumentService,
+        "insert",
+        lambda _payload: SimpleNamespace(to_json=lambda: {"file_id": "inner-1", "document_id": "doc-new"}),
+    )
+    res = _run(module.convert())
+    assert res["code"] == 0
+    assert res["data"] == [{"file_id": "inner-1", "document_id": "doc-new"}]
+
+    req_state["file_ids"] = ["f1"]
+    monkeypatch.setattr(
+        module.FileService,
+        "get_by_ids",
+        lambda _ids: (_ for _ in ()).throw(RuntimeError("convert boom")),
+    )
+    res = _run(module.convert())
+    assert res["code"] == 500
+    assert "convert boom" in res["message"]
+
+
+@pytest.mark.p2
+def test_rm_branch_matrix_unit(monkeypatch):
+    module = _load_file2document_module(monkeypatch)
+    req_state = {"file_ids": []}
+    _set_request_json(monkeypatch, module, req_state)
+
+    deleted = []
+
+    res = _run(module.rm())
+    assert res["code"] == module.RetCode.ARGUMENT_ERROR
+    assert 'Lack of "Files ID"' in res["message"]
+
+    req_state["file_ids"] = ["f1"]
+    monkeypatch.setattr(module.File2DocumentService, "get_by_file_id", lambda _file_id: [])
+    res = _run(module.rm())
+    assert res["message"] == "Inform not found!"
+
+    monkeypatch.setattr(module.File2DocumentService, "get_by_file_id", lambda _file_id: [None])
+    res = _run(module.rm())
+    assert res["message"] == "Inform not found!"
+
+    monkeypatch.setattr(module.File2DocumentService, "get_by_file_id", lambda _file_id: [SimpleNamespace(document_id="doc-1")])
+    monkeypatch.setattr(module.File2DocumentService, "delete_by_file_id", lambda file_id: deleted.append(file_id))
+    monkeypatch.setattr(module.DocumentService, "get_by_id", lambda _doc_id: (False, None))
+    res = _run(module.rm())
+    assert res["message"] == "Document not found!"
+    assert deleted == ["f1"]
+
+    monkeypatch.setattr(module.DocumentService, "get_by_id", lambda _doc_id: (True, SimpleNamespace(id=_doc_id)))
+    monkeypatch.setattr(module.DocumentService, "get_tenant_id", lambda _doc_id: None)
+    res = _run(module.rm())
+    assert res["message"] == "Tenant not found!"
+
+    monkeypatch.setattr(module.DocumentService, "get_tenant_id", lambda _doc_id: "tenant-1")
+    monkeypatch.setattr(module.DocumentService, "remove_document", lambda *_args, **_kwargs: False)
+    res = _run(module.rm())
+    assert "Document removal" in res["message"]
+
+    req_state["file_ids"] = ["f1", "f2"]
+    monkeypatch.setattr(
+        module.File2DocumentService,
+        "get_by_file_id",
+        lambda file_id: [SimpleNamespace(document_id=f"doc-{file_id}")],
+    )
+    monkeypatch.setattr(module.DocumentService, "get_by_id", lambda doc_id: (True, SimpleNamespace(id=doc_id)))
+    monkeypatch.setattr(module.DocumentService, "get_tenant_id", lambda _doc_id: "tenant-1")
+    monkeypatch.setattr(module.DocumentService, "remove_document", lambda *_args, **_kwargs: True)
+    res = _run(module.rm())
+    assert res["code"] == 0
+    assert res["data"] is True
+
+    monkeypatch.setattr(
+        module.File2DocumentService,
+        "get_by_file_id",
+        lambda _file_id: (_ for _ in ()).throw(RuntimeError("rm boom")),
+    )
+    req_state["file_ids"] = ["boom"]
+    res = _run(module.rm())
+    assert res["code"] == 500
+    assert "rm boom" in res["message"]