Install libpython2.7-testsuite by entering the following commands in the terminal:
sudo apt update sudo apt install libpython2.7-testsuite
Testsuite for the Python standard library (v2.7)
The complete testsuite for the Python standard library. Note that a subset is found in the libpython2.7-stdlib package, which should be enough for other packages to use (please do not build-depend on this package, but file a bug report to include additional testsuite files in the libpython2.7-stdlib package).