tests: improve test_pdb_interaction_doctest
tests: improve test_pdb_interaction_doctest

- ignore pdbrc (might be done in general, but this was the only affected
  test)
- fail faster in case of unexpected failure

Akasurde/pytest,The-Compiler/pytest,pytest-dev/pytest,RonnyPfannschmidt/pytest,tomviner/pytest,The-Compiler/pytest,markshao/pytest,nicoddemus/pytest,alfredodeza/pytest,tomviner/pytest,nicoddemus/pytest