I investigated a bit more, it seems that cover is wrong. In a bullseye chroot it works
$ python3 ./test.py (bullseye_mips64el-dchroot)picca@eller:~/matplotlib-3.5.0/build/lib.linux-mips64-3.9$ ls matplotlib mpl_toolkits pylab.py test.py toto.png I found that the test failed between the 3.3.4-2 and 3.3.4-2+b1 rebuild This binNMU was about python3.10 support, but in the same time numpy has changed from python3-numpy (= 1:1.19.5-1), to python3-numpy (= 1:1.21.4-2), I think that there is a non negligeable possibility for this bug to be triggered by the new numpy.
