flask应用程序测试中的请求没有文件

<form method="POST" enctype="multipart/form-data">
    <input type="file" name="file">
    <input type="submit" value="Upload">
</form>

from flask import Flask, request

app = Flask(__name__)

@app.route('/upload', methods=['POST'])
def upload_file():
    if 'file' not in request.files:
        return "No file part in the request", 400
    file = request.files['file']
    if file.filename == '':
        return "No selected file", 400
    if file:
        # 处理文件上传逻辑
        file.save(f"./uploads/{file.filename}")
        return "File uploaded successfully", 200

import pytest
from flask import Flask, request

app = Flask(__name__)

@app.route('/upload', methods=['POST'])
def upload_file():
    if 'file' not in request.files:
        return "No file part in the request", 400
    file = request.files['file']
    if file.filename == '':
        return "No selected file", 400
    if file:
        file.save(f"./uploads/{file.filename}")
        return "File uploaded successfully", 200

@pytest.fixture
def client():
    app.config['TESTING'] = True
    with app.test_client() as client:
        yield client

def test_upload_file(client):
    file = open('test_file.txt', 'rb')
    response = client.post('/upload', data={'file': (file, 'test_file.txt')})
    assert response.status_code == 200
    assert b'File uploaded successfully' in response.data