pytest文档80 - 内置 fixtures 之 cache 写入中文显示\u4e2d\u6587问题(用打补丁方式解决)

前言

pytest 内置 fixtures 之 cache 写入中文的时候会在文件中写入\u4e2d\u6587 这种unicode编码格式。
如果想在文件中显示正常的中文，需重新Cache类的set方法来解决

问题描述

pytest 用例 cache 的使用参考前面这篇https://www.cnblogs.com/yoyoketang/p/15747082.html
当cache设置中文的时候,写入cache文件中文显示

问题原因

出现这个问题的根本原因是python3 的json库留下来的一个坑，先看以下简单的实例

import json

a = '上海-悠悠'
print(json.dumps(a))

# ensure_ascii=False
print(json.dumps(a, ensure_ascii=False))

运行结果

"\u4e0a\u6d77-\u60a0\u60a0"
"上海-悠悠"

使用json调用dumps方法的时候默认ensure_ascii参数为True

def dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True,
        allow_nan=True, cls=None, indent=None, separators=None,
        default=None, sort_keys=False, **kw):

所以会导致中文在转json的时候，是以\u4e0a\u6d77这种编码格式显示的.

Cache类的set方法

pytest 内置 fixtures 之 cache 是 Cache 类的实例,看下 Cache 类的 set 方法实现

def set(self, key: str, value: object) -> None:
        """Save value for the given key.

        :param key:
            Must be a ``/`` separated value. Usually the first
            name is the name of your plugin or your application.
        :param value:
            Must be of any combination of basic python types,
            including nested types like lists of dictionaries.
        """
        path = self._getvaluepath(key)
        try:
            if path.parent.is_dir():
                cache_dir_exists_already = True
            else:
                cache_dir_exists_already = self._cachedir.exists()
                path.parent.mkdir(exist_ok=True, parents=True)
        except OSError:
            self.warn("could not create cache path {path}", path=path, _ispytest=True)
            return
        if not cache_dir_exists_already:
            self._ensure_supporting_files()
        data = json.dumps(value, indent=2, sort_keys=True)
        try:
            f = path.open("w")
        except OSError:
            self.warn("cache could not write path {path}", path=path, _ispytest=True)
        else:
            with f:
                f.write(data)

这里面有一句json.dumps没传ensure_ascii参数

data = json.dumps(value, indent=2, sort_keys=True)

问题原因找到了，接下来打个补丁，重写set方法即可

打补丁

以下这段补丁代码加到运行用例之前，放到项目根目录conftest.py文件的开始位置即可

from _pytest.cacheprovider import Cache
import json
"""
作者：上海-悠悠
python QQ交流群：730246532
联系微信/QQ: 283340479
"""

def new_set(self, key: str, value: object) -> None:
    """Save value for the given key.

    :param key:
        Must be a ``/`` separated value. Usually the first
        name is the name of your plugin or your application.
    :param value:
        Must be of any combination of basic python types,
        including nested types like lists of dictionaries.
    """
    path = self._getvaluepath(key)
    try:
        if path.parent.is_dir():
            cache_dir_exists_already = True
        else:
            cache_dir_exists_already = self._cachedir.exists()
            path.parent.mkdir(exist_ok=True, parents=True)
    except OSError:
        self.warn("could not create cache path {path}", path=path, _ispytest=True)
        return
    if not cache_dir_exists_already:
        self._ensure_supporting_files()
    data = json.dumps(value, ensure_ascii=False, indent=2, sort_keys=True)
    try:
        f = path.open("w", encoding='utf-8')
    except OSError:
        self.warn("cache could not write path {path}", path=path, _ispytest=True)
    else:
        with f:
            f.write(data)

Cache.set = new_set

主要改动2个地方

# 添加一个参数 ensure_ascii=False
data = json.dumps(value, ensure_ascii=False, indent=2, sort_keys=True)
# 添加一个参数 encoding='utf-8'
f = path.open("w", encoding='utf-8')

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