前言

近期在学习用airtest进行自动化测试，遇到的坑来记录一下。

问题

用pycharm学习airtest的时候发现任何poco的函数都会直接报错raise JSONDecodeError("Expecting value", s, err.value) from None异常，进行debug后发现问题出在minicap.py文件的get_display_info方法里面。
get_display_info代码

def get_display_info(self):      display_info = self.adb.shell("%s -i" % self.CMD)     display_info = json.loads(display_info)     display_info["orientation"] = display_info["rotation"] / 90     # 针对调整过手机分辨率的情况     actual = self.adb.shell("dumpsys window displays")     arr = re.findall(r'cur=(/d+)x(/d+)', actual)     if len(arr) > 0:         display_info['physical_width'] = display_info['width']         display_info['physical_height'] = display_info['height']         # 通过 adb shell dumpsys window displays | find "cur="         # 获取到的分辨率是实际分辨率，但是需要的是非实际的         if display_info["orientation"] in [1, 3]:             display_info['width'] = int(arr[0][1])             display_info['height'] = int(arr[0][0])         else:             display_info['width'] = int(arr[0][0])             display_info['height'] = int(arr[0][1])     return display_info 

这个方法会被传一条命令进来 LD_LIBRARY_PATH=/data/local/tmp /data/local/tmp/minicap -i ; echo ---$?---

执行之后会返回这些

WARNING: linker: /data/local/tmp/minicap has text relocations. This is wasting memory and prevents security hardening. Please fix.  {      "id": 0,      "width": 540,      "height": 960,      "xdpi": 240.00,      "ydpi": 240.00,      "size": 4.59,      "density": 1.50,      "fps": 60.00,      "secure": true,      "rotation": 0  } 

很明显里面多了一句警告，导致了**json.loads(display_info)**时候报错，下面我们改造一下这段代码。

添加如下两行

index = display_info.index("{") display_info = display_info[index:len(display_info)] 

最后代码如下

def get_display_info(self):     display_info = self.adb.shell("%s -i" % self.CMD)     index = display_info.index("{")     display_info = display_info[index:len(display_info)]     display_info = json.loads(display_info)     display_info["orientation"] = display_info["rotation"] / 90     # 针对调整过手机分辨率的情况     actual = self.adb.shell("dumpsys window displays")     arr = re.findall(r'cur=(/d+)x(/d+)', actual)     if len(arr) > 0:         display_info['physical_width'] = display_info['width']         display_info['physical_height'] = display_info['height']         # 通过 adb shell dumpsys window displays | find "cur="         # 获取到的分辨率是实际分辨率，但是需要的是非实际的         if display_info["orientation"] in [1, 3]:             display_info['width'] = int(arr[0][1])             display_info['height'] = int(arr[0][0])         else:             display_info['width'] = int(arr[0][0])             display_info['height'] = int(arr[0][1])     return display_info