Parallel build failure on CircleCI #9872

============================= test session starts ==============================
platform linux -- Python 3.6.10, pytest-5.3.4, py-1.8.1, pluggy-0.13.1

Running tests with Astropy version 4.1.dev27325.
Running tests in astropy docs.

Date: 2020-01-21T09:55:41

Platform: Linux-4.15.0-1052-aws-x86_64-with-redhat-5.11-Final

Executable: /opt/python/cp36-cp36m/bin/python

Full Python Version: 
3.6.10 (default, Jan 13 2020, 05:55:32) 
[GCC 4.8.2 20140120 (Red Hat 4.8.2-15)]

encodings: sys: utf-8, locale: UTF-8, filesystem: utf-8
byteorder: little
float info: dig: 15, mant_dig: 15

Package versions: 
Numpy: 1.16.6
Scipy: 1.4.1
Matplotlib: not available
h5py: not available
Pandas: not available
Cython: 0.29.14
Scikit-image: not available
asdf: not available
astropy-helpers: 4.0.1

Using Astropy options: remote_data: none.

rootdir: /tmp/astropy-test-00u8183c/lib/python3.6/site-packages, inifile: setup.cfg
plugins: forked-1.1.3, hypothesis-5.3.0, xdist-1.31.0, doctestplus-0.5.0, remotedata-0.3.2, astropy-header-0.1.2, openfiles-0.4.0, cov-2.8.1, filter-subpackage-0.1.1, arraydiff-0.3

gw0 I / gw1 I / gw2 I / gw3 I
gw0 C / gw1 I / gw2 I / gw3 I
gw0 C / gw1 C / gw2 I / gw3 I
gw0 C / gw1 C / gw2 C / gw3 I
gw0 C / gw1 C / gw2 C / gw3 C
gw0 ok / gw1 C / gw2 C / gw3 C
gw0 ok / gw1 ok / gw2 C / gw3 C
gw0 ok / gw1 ok / gw2 C / gw3 ok
gw0 ok / gw1 ok / gw2 ok / gw3 ok
collecting 0 items / 1 skipped                                                 
collecting 0 items / 16 skipped                                                
gw0 ok / gw1 [14299] / gw2 ok / gw3 ok
gw0 [14299] / gw1 [14299] / gw2 ok / gw3 ok
gw0 [14299] / gw1 [14299] / gw2 ok / gw3 [14299]
gw0 [14299] / gw1 [14299] / gw2 [14299] / gw3 [14299]
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........s............sssssssssssss.ssssxss.s.s......s.ss..........s..xx. [ 10%]
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..........................INTERNALERROR> Traceback (most recent call last):
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/_pytest/main.py", line 197, in wrap_session
INTERNALERROR>     session.exitstatus = doit(config, session) or 0
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/_pytest/main.py", line 247, in _main
INTERNALERROR>     config.hook.pytest_runtestloop(session=session)
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/pluggy/hooks.py", line 286, in __call__
INTERNALERROR>     return self._hookexec(self, self.get_hookimpls(), kwargs)
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/pluggy/manager.py", line 93, in _hookexec
INTERNALERROR>     return self._inner_hookexec(hook, methods, kwargs)
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/pluggy/manager.py", line 87, in <lambda>
INTERNALERROR>     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/pluggy/callers.py", line 208, in _multicall
INTERNALERROR>     return outcome.get_result()
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/pluggy/callers.py", line 80, in get_result
INTERNALERROR>     raise ex[1].with_traceback(ex[2])
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/pluggy/callers.py", line 187, in _multicall
INTERNALERROR>     res = hook_impl.function(*args)
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/xdist/dsession.py", line 112, in pytest_runtestloop
INTERNALERROR>     self.loop_once()
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/xdist/dsession.py", line 135, in loop_once
INTERNALERROR>     call(**kwargs)
INTERNALERROR>   File "/opt/python/cp36-cp36m/lib/python3.6/site-packages/xdist/dsession.py", line 177, in worker_workerfinished
INTERNALERROR>     assert not crashitem, (crashitem, node)
INTERNALERROR> AssertionError: ('astropy/io/ascii/tests/test_read.py::test_missing_file', <WorkerController gw1>)
INTERNALERROR> assert not 'astropy/io/ascii/tests/test_read.py::test_missing_file'