code: def test_post_file(tmp_path):
      path = tmp_path / "test.txt"
      path.write_bytes(b"<file content>")
  
      client = TestClient(app)
      with path.open("rb") as file:
          response = client.post("/files/", files={"file": file})
      assert response.status_code == 200, response.text
      assert response.json() == {"file_size": 14}
  
imports: from dirty_equals import IsDict
  from fastapi.testclient import TestClient
  from docs_src.request_files.tutorial001_02 import app
label_desc: Use image node_id 3 for calling a global function with example usage: test_post_file(tmp_path) without return types