-c do not work for utf-8!

[hsz1273327]

my code:

# coding:utf-8
from __future__ import print_function

class Dog(object):

def __str__(self):
    return "<Dog:{self.name}--{self.age}>".format(self=self)

def __repr__(self):
    return self.__str__()

def __init__(self, name, age):
    self.name = name
    self.age = age

def eat(self, food):
    return "{self.name} is eating {food}".format(self=self, food=food)

> testcode:

```python
# coding:utf-8
from __future__ import print_function,absolute_import

from pyvows import Vows,expect
import sys
import os
from forgery_py import name as random_name
from random import randint

root = os.path.dirname(os.path.dirname(__file__))
sys.path[0] = root

import dog


@Vows.batch
class DogTest(Vows.Context):
    def topic(self):
        name = random_name.full_name()
        age = randint(18,30)
        return dog.Dog(name,age)

    def can_eat(self, topic):
        food = "apple"
        expect(topic.eat(food)).to_equal("{topic.name} is eating {food}".format(topic=topic, food=food))

    def can_be_print(self, topic):
        expect(str(topic)).to_equal("<Dog:{topic.name}--{topic.age}>".format(topic=topic))

command:

pyvows test/ --pattern='*_test.py' -cover

result:

============
 Vows Results
 ============

✓ OK » 2 honored • 0 broken (0.004289s)

/Users/huangsizhe/Lib/conda/anaconda/lib/python2.7/genericpath.py:80: UnicodeWarning: Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal
s1 = min(m)
Could not run coverage. Error: 'ascii' codec can't decode byte 0xe5 in position 0: ordinal not in range(128)