python - 如何在异步单元测试中模拟方法？

Question

我有一个名为 database.py 的类，其中有一个名为 generate_token() 的函数。
我想模拟它并返回一个固定值 321 .这样我就可以看到调用了该方法并返回了返回值。
我如何 mock 它？这是我尝试过的。

@pytest.mark.asyncio
async def test_successful_register_returns_device_token(monkeypatch):
    async def mock_generate_token():
        return "321"

    m = AsyncMock(mock_generate_token)
    m.return_value = "321"
    async with AsyncClient(app=app, base_url="http://127.0.0.1") as ac:
        monkeypatch.setattr(database, "generate_token", m)
        response = await ac.post(
            "/register/",
            headers={},
            json={},
        )
        assert response.status_code == 201
        assert "device_token" in response.json()
        assert response.json()["device_token"] == "321"

Answer 1

它实际上比我想象的要简单得多，来自 from unittest.mock import patch 的普通@patch足够了。它识别异步方法并自动注入(inject) AsyncMock。

@pytest.mark.asyncio
@patch("service.auth_service.AuthService.generate_token")
async def test_successful_register_returns_device_token(self, mock_token):
        mock_token.return_value = "321"
        async with AsyncClient(app=app, base_url="http://testserver") as ac:
            response = await ac.post(
                "/register/",
                headers={},
                json={},
            )
            assert response.status_code == 201
            assert "device_token" in response.json()
            assert response.json()["device_token"] == "321"