CI: better cleanup for modules in between tests

tests/common.py

@@ -7,3 +7,14 @@ V = 'HPI_TESTS_KARLICOSS'
 skip_if_not_karlicoss = pytest.mark.skipif(
     V not in os.environ, reason=f'test only works on @karlicoss data for now. Set evn variable {V}=true to override.',
 )
+
+def reset_modules() -> None:
+    '''
+    A hack to 'unload' HPI modules, otherwise some modules might cache the config
+    TODO: a bit crap, need a better way..
+    '''
+    import sys
+    import re
+    to_unload = [m for m in sys.modules if re.match(r'my[.]?', m)]
+    for m in to_unload:
+        del sys.modules[m]