Try to fix async tests.

us trio instead of asyncio as we can't run nested loops.

.travis.yml

@@ -37,7 +37,7 b' install:'
   - pip install -e file://$PWD#egg=ipython[test] --upgrade
   - pip install trio curio --upgrade --upgrade-strategy eager
   - pip install 'pytest' 'matplotlib !=3.2.0'
-  - pip install codecov check-manifest pytest-cov --upgrade anyio pytest-asyncio
+  - pip install codecov check-manifest pytest-cov --upgrade anyio pytest-trio
 
 
 script:

IPython/core/tests/test_magic.py

@@ -35,6 +35,8 b' from IPython.utils.tempdir import (TemporaryDirectory,'
 from IPython.utils.process import find_cmd
 from .test_debugger import PdbTestInput
 
+import pytest
+
 
 @magic.magics_class
 class DummyMagics(magic.Magics): pass
@@ -954,7 +956,6 b' async def test_script_bg_out():'
     nt.assert_equal((await ip.user_ns["output"].read()), b"hi\n")
     ip.user_ns['output'].close()
 
-
 @dec.skip_win32
 async def test_script_bg_err():
     ip = get_ipython()