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testing: "There is no current event loop in thread 'MainThread'."

See original GitHub issue

First Check

  • I added a very descriptive title to this issue.
  • I used the GitHub search to find a similar issue and didn’t find it.
  • I searched the FastAPI documentation, with the integrated search.
  • I already searched in Google “How to X in FastAPI” and didn’t find any information.
  • I already read and followed all the tutorial in the docs and didn’t find an answer.
  • I already checked if it is not related to FastAPI but to Pydantic.
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Commit to Help

  • I commit to help with one of those options 👆

Example Code

I have several modules with unit-tests: test_sum.py

import pytest
from httpx import AsyncClient

pytestmark = pytest.mark.anyio


async def test_sum(app):
    async with AsyncClient(app=app, base_url='http://127.0.0.1:5000') as ac:
        response = await ac.post('/v1/sum', json={"x": 4, "y": 6})

    assert response.status_code == 200
    assert response.json() == {"sum": 10}

test_items.py

from tests.expected_data import created_item
from tests.moks_data import items

pytestmark = pytest.mark.anyio


async def test_create_item(app):
    async with AsyncClient(app=app, base_url='http://test') as ac:
        response = await ac.post('/v1/items', json={
            "name": "TestName",
            "description": "Test description",
            "price": 100
        })

    assert response.status_code == 200
    assert response.json() == created_item


async def test_get_item(fill_db, app):
    async with AsyncClient(app=app, base_url='http://test') as ac:
        response = await ac.get('/v1/items/2')

    assert response.status_code == 200
    assert response.json() == items[1]

conftest.py

import pytest
from alembic.command import downgrade, upgrade
from alembic.config import Config as AlembicConfig

from core.app.web import create_app
from core.data.postgres.engine import session_scope
from core.data.postgres.models import Base, Item
from tests.moks_data import items


@pytest.fixture
def app():
    app_instance = create_app()
    return app_instance

@pytest.fixture(scope='session')
def db_session():
    config = AlembicConfig('alembic.ini')
    config.attributes['configure_logger'] = False

    upgrade(config, 'head')

    yield 'on head'

    downgrade(config, 'base')


@pytest.fixture(autouse=True)
async def clear_data(db_session):
    yield 'I will clear tables for you'

    reference_value_tables = [f'{name}' for name in ('role',)]

    async with session_scope() as session:
        for name, table in Base.metadata.tables.items():
            if name not in reference_value_tables:
                await session.execute(table.delete())


@pytest.fixture
async def fill_db(event_loop):
    items_list = [Item(**item) for item in items]
    async with session_scope() as session:
        session.add_all(items_list)
        await session.flush()

Description

I’m using: python 3.10.1, fastapi 0.72.0, pytest 6.2.5, pytest-trio 0.7.0, sqlalchemy 1.4.31, alembic 1.7.5, asyncpg 0.25.0, postgresql 14.1.** Now, i have issue when i try to execute my tests.

When i run my tests - tests in test_sum is successfully ended but tests in test_items is failed with error: There is no current event loop in thread 'MainThread'.

Please tell me what I’m doing wrong and how to solve this problem?

Operating System

Linux

Operating System Details

manjaro linux 21.2.1

FastAPI Version

0.72.0

Python Version

3.10.1

Additional Context

tests work correctly with fastapi <= 0.68

Issue Analytics

  • State:closed
  • Created 2 years ago
  • Comments:7

github_iconTop GitHub Comments

1reaction
alextedcommented, Jul 18, 2022
0reactions
mateusz-chrzastekcommented, Jul 15, 2022

I encountered this when writing my tests as asynchronous tests (async def test_xyz) with asyncpg and pytest-asyncio.

I found an alternate solution by opting for non-async def test_xyz tests and removing any class wrapper! (Which is what broke regular tests for me). While this doesn’t resolve being able to run async code in tests, I was able to test my endpoints this way.

Read more comments on GitHub >

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