import sys
import json
import subprocess


IMPORT_TEST = b'''\
try:
    import __builtin__ as builtins
except ImportError:
    import builtins

found_imports = set()
real_import = builtins.__import__
import sys

def tracking_import(module, locals=None, globals=None, fromlist=None,
                    level=0):
    rv = real_import(module, locals, globals, fromlist, level)
    if globals and globals['__name__'].startswith('click') and level == 0:
        found_imports.add(module)
    return rv
builtins.__import__ = tracking_import

import click
rv = list(found_imports)
import json
click.echo(json.dumps(rv))
'''

ALLOWED_IMPORTS = set([
    'weakref', 'os', 'struct', 'collections', 'sys', 'contextlib',
    'functools', 'stat', 're', 'codecs', 'inspect', 'itertools', 'io'
])


def test_light_imports():
    c = subprocess.Popen([sys.executable, '-'], stdin=subprocess.PIPE,
                         stdout=subprocess.PIPE)
    rv = c.communicate(IMPORT_TEST)[0]

    if sys.version_info[0] != 2:
        rv = rv.decode('utf-8')
    imported = json.loads(rv)
    print(imported)

    for module in imported:
        if module == 'click' or module.startswith('click.'):
            continue
        assert module in ALLOWED_IMPORTS