test failures: TypeError: 'NoneType' object does not support item assignment

[0-wiz-0]

With 1.8.1, I see two new test failures with python-3.6 on NetBSD in an ASCII locale:

___________________________________________________________ ERROR collecting tests/hazmat/backends/test_openssl.py ___________________________________________________________
tests/hazmat/backends/test_openssl.py:622: in <module>
    class TestOpenSSLDHSerialization(object):
tests/hazmat/backends/test_openssl.py:628: in TestOpenSSLDHSerialization
    load_nist_vectors))
tests/utils.py:77: in load_vectors_from_file
    return loader(vector_file)
tests/utils.py:111: in load_nist_vectors
    test_data[name.lower()] = value.encode("ascii")
E   TypeError: 'NoneType' object does not support item assignment
____________________________________________________________ ERROR collecting tests/hazmat/primitives/test_dh.py _____________________________________________________________
tests/hazmat/primitives/test_dh.py:146: in <module>
    class TestDH(object):
tests/hazmat/primitives/test_dh.py:163: in TestDH
    load_nist_vectors))
tests/utils.py:77: in load_vectors_from_file
    return loader(vector_file)
tests/utils.py:111: in load_nist_vectors
    test_data[name.lower()] = value.encode("ascii")
E   TypeError: 'NoneType' object does not support item assignment
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 2 errors during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
==================================================================== 4 skipped, 2 error in 22.86 seconds =====================================================================
*** Error code 2

[alex]

Unfortunately none of us have a NetBSD env, so we could use some assistance in debugging this.

Do the tests for the vector loaders pass?

[0-wiz-0]

When I just now ran the tests again, they all worked:
83280 passed, 3243 skipped in 246.76 seconds
The machine has had a lot of memory pressure lately, could that explain it?
Anyway, I'll come back if the problem resurfaces. Thanks.