import sys
import os
import linecache
import types
from collections import Counter

def find_duplicates(top):
    duplicates = []
    for dirpath, dirnames, filenames in os.walk(top):
        for fname in filenames:
            root, ext = os.path.splitext(fname)
            if ext != '.py':
                continue
            filename = os.path.join(dirpath, fname)
            try:
                source_lines = linecache.getlines(filename)
                code = compile(''.join(source_lines), filename, 'exec')
            except:
                continue
            duplicates.extend((filename, name) for name, cnt in
                    Counter(testmethod_names(code)).items() if cnt > 1)

    if duplicates:
        print('Duplicate test method names:')
    for filename, name in duplicates:
        print('{}: {}'.format(filename, name))

def testmethod_names(code, name=[]):
    name = name + [code.co_name]
    for c in code.co_consts:
        if isinstance(c, types.CodeType):
            for item in testmethod_names(c, name):
                yield item
    if name[-1].startswith('test_'):
        yield '.'.join(name)

if __name__ == "__main__":
    if len(sys.argv) != 2 or not os.path.isdir(sys.argv[1]):
        print('A directory pathname is required.', file=sys.stderr)
        sys.exit(1)
    find_duplicates(sys.argv[1])