nilmdb/tests/test_mustclose.py

import nilmdb
from nilmdb.utils.printf import *

import nose
from nose.tools import *
from nose.tools import assert_raises

from test_helpers import *

import sys
import cStringIO

err = cStringIO.StringIO()

@nilmdb.utils.must_close(errorfile = err)
class Foo:
    def __init__(self):
        fprintf(err, "Init\n")

    def __del__(self):
        fprintf(err, "Deleting\n")

    def close(self):
        fprintf(err, "Closing\n")

@nilmdb.utils.must_close(errorfile = err)
class Bar:
    pass

class TestMustClose(object):
    def test(self):

        # Note: this test might fail if the Python interpreter doesn't
        # garbage collect the object (and call its __del__ function)
        # right after a "del x".

        x = Foo()
        del x
        eq_(err.getvalue(),
            "Init\n"
            "error: Foo.close() wasn't called!\n"
            "Deleting\n")

        err.truncate(0)

        y = Foo()
        y.close()
        del y
        eq_(err.getvalue(),
            "Init\n"
            "Closing\n"
            "Deleting\n")

        err.truncate(0)

        z = Bar()
        z.close()
        del z
        eq_(err.getvalue(), "")