move from optparse to argparse

.coveragerc

@@ -1,11 +1,31 @@
 [run]
+parallel = True
 branch = True
 source =
     flake8
-
+omit =
+    # Don't complain if non-runnable code isn't run
+    */__main__.py
 
 [paths]
 source =
     src/flake8
     .tox/*/lib/python*/site-packages/flake8
     .tox/pypy/site-packages/flake8
+
+[report]
+show_missing = True
+skip_covered = True
+exclude_lines =
+    # Have to re-enable the standard pragma
+    \#\s*pragma: no cover
+
+    # Don't complain if tests don't hit defensive assertion code:
+    ^\s*raise AssertionError\b
+    ^\s*raise NotImplementedError\b
+    ^\s*return NotImplemented\b
+    ^\s*raise$
+
+    # Don't complain if non-runnable code isn't run:
+    ^if __name__ == ['"]__main__['"]:$
+    ^\s*if False: