Tests on Windows x86 with Julia nightly have been failing for all Python versions since (at least) Julia 1.2.0-DEV.641 (logs). This still happened in the latest tests on PyCall master with Julia 1.3.0-DEV.2 (logs). The last success was with Julia 1.2.0-DEV.570 (logs).
The error happens in __pycall!:
Exception: EXCEPTION_ACCESS_VIOLATION at 0xff60240 -- unknown function (ip: 0FF60240)
in expression starting at C:\projects\pycall-jl-nu3aa\test\runtests.jl:29
unknown function (ip: 0FF6023F)
PyObject_Call at C:\Python37\python37.dll (unknown line)
macro expansion at C:\projects\pycall-jl-nu3aa\src\exception.jl:81 [inlined]
__pycall! at C:\projects\pycall-jl-nu3aa\src\pyfncall.jl:44
_pycall! at C:\projects\pycall-jl-nu3aa\src\pyfncall.jl:29
_pycall! at C:\projects\pycall-jl-nu3aa\src\pyfncall.jl:11 [inlined]
#pycall#110 at C:\projects\pycall-jl-nu3aa\src\pyfncall.jl:86 [inlined]
pycall at C:\projects\pycall-jl-nu3aa\src\pyfncall.jl:86
https://ci.appveyor.com/project/StevenGJohnson/pycall-jl-nu3aa/builds/23785003/job/rm9dhp093rs6ab8x#L99