[Answered ]-When i execute unittest command "python3 -m unittest filepath/filename.py" it showing improperly configured error

You need to set which settings file you need to run the unit test.

on Linux

$ export DJANGO_SETTINGS_MODULE=your_setting

please read this https://docs.djangoproject.com/en/dev/internals/contributing/writing-code/unit-tests/#testing-other-python-versions-and-database-backends