test: add test for FileComponent component

src/backend/tests/unit/components/data/test_file_component.py

@@ -0,0 +1,63 @@
+from unittest.mock import Mock
+
+import pytest
+from langflow.components.data import FileComponent
+
+from tests.base import ComponentTestBaseWithoutClient
+
+
+class TestFileComponent(ComponentTestBaseWithoutClient):
+    @pytest.fixture
+    def component_class(self):
+        return FileComponent
+
+    @pytest.fixture
+    def default_kwargs(self):
+        return {"use_multithreading": True, "concurrency_multithreading": 2, "_session_id": "123"}
+
+    @pytest.fixture
+    def file_names_mapping(self):
+        return []
+
+    def test_process_files_with_no_files(self, component_class, default_kwargs):
+        component = component_class(**default_kwargs)
+        with pytest.raises(ValueError, match="No files to process."):
+            component.process_files([])
+
+    def test_process_files_sequentially(self, component_class, default_kwargs, tmp_path):
+        file1 = tmp_path / "file1.txt"
+        file2 = tmp_path / "file2.txt"
+        file1.write_text("content 1")
+        file2.write_text("content 2")
+        default_kwargs["use_multithreading"] = False
+
+        component = component_class(**default_kwargs)
+        mock_file_list = [Mock(path=str(file1)), Mock(path=str(file2))]
+        result = component.process_files(mock_file_list)
+
+        assert all(i.path in (str(file1), str(file2)) for i in result)
+
+    def test_process_files_with_multithreading(self, component_class, default_kwargs, tmp_path):
+        mock_file_list = []
+        files = []
+        for i in range(5):
+            file = tmp_path / f"file{i}.txt"
+            file.write_text(f"content {i}")
+            files.append(file)
+            mock_file_list.append(Mock(path=str(file)))
+
+        component = component_class(**default_kwargs)
+        result = component.process_files(mock_file_list)
+
+        assert all(i.path in [f.path for f in mock_file_list] for i in result)
+
+    def test_file_component_latest(self, component_class, default_kwargs, tmp_path):
+        file = tmp_path / "latest_file.txt"
+        file.write_text("latest content")
+
+        component = component_class(**default_kwargs)
+        mock_file_list = [Mock(path=str(file))]
+        result = component.process_files(mock_file_list)
+
+        assert len(result) == len(mock_file_list)
+        assert all(i.path in [f.path for f in mock_file_list] for i in result)