Fixed bug in run_tests.
Fixed bug in run_tests.

* Previously we were modifying a list while we were iterating through
  it giving us undefined behavior. Fix is to make a copy of the list.

galah-group/galah-interact-python,galah-group/galah-interact-python,galah-group/galah-interact-python,ucrcsedept/galah-interact-python,ucrcsedept/galah-interact-python,ucrcsedept/galah-interact-python