在 python 测试期间忽略颜色序列

Question

相关： timofurrer/colorful#23

---

我正在重新实现pure prompt in python，以便它可以支持更多的外壳。

但是，在测试颜色时，我得到了“意外”的行为，即我不明白的行为。

测试输出

    def test_prompt_symbol_is_colored_for_successful_command():
        assert str(prompt.prompt_symbol()) == str(colors.primary('❯'))
>       assert str(prompt.prompt_symbol()) == '\x1b[38;2;155;48;255m❯\x1b[39m'
E       AssertionError: assert '❯' == '\x1b[38;2;155;48;255m❯\x1b[39m'
E         - ❯
E         + ❯   ← this one is purple

_colors_test.py_

def test_prompt_symbol_is_colored_for_successful_command():
    assert str(prompt.prompt_symbol()) == str(colors.primary('❯'))
    assert str(prompt.prompt_symbol()) == '\x1b[38;2;155;48;255m❯\x1b[39m'

我运行测试：

pytest -v tests/

colors.py

import colorful

primary = colorful.purple1
mute = colorful.gray

prompt.py

from pure import colors

def prompt_symbol(last_command_status=0):
    symbol = colors.primary('❯') if last_command_status == 0 else colors.danger('❯')
    return symbol

问题

第一个断言成功，而第二个断言失败，尽管它们应该是等效的。当我否定第一个断言时，转义序列不存在：

>       assert str(prompt.prompt_symbol()) != str(colors.primary('❯'))
E       AssertionError: assert '❯' != '❯'
E        +  where '❯' = str(<colorful.core.ColorfulString object at 0x7f545276f080>)
E        +    where <colorful.core.ColorfulString object at 0x7f545276f080> = <function prompt_symbol at 0x7f54527b79d8>()
E        +      where <function prompt_symbol at 0x7f54527b79d8> = prompt.prompt_symbol
E        +  and   '❯' = str(<colorful.core.ColorfulString object at 0x7f545276f0b8>)
E        +    where <colorful.core.ColorfulString object at 0x7f545276f0b8> = <colorful.core.Colorful.ColorfulStyle object at 0x7f54527c2278>('❯')
E        +      where <colorful.core.Colorful.ColorfulStyle object at 0x7f54527c2278> = colors.primary

在 python REPL 中手动执行命令给了我：

>>> from pure import colors, prompt 
>>> str(colors.primary('❯'))
'\x1b[38;2;155;48;255m❯\x1b[39m'
>>> str(prompt.prompt_symbol())
'\x1b[38;2;155;48;255m❯\x1b[39m'

Answer 1

用--capture=no (or -s) flag from pytest修复：

pytest -v --capture=no tests/

详情请见https://github.com/timofurrer/colorful/issues/23#issuecomment-468008070。