sikuli和Robotframework集成若干问题（一）：TypeError: exists(): 2nd arg can't be coerced to double

很多同学在集成sikuli和Robotframework的时候，都参考了http://blog.mykhailo.com/2011/02/how-to-sikuli-and-robot-framework.html这篇经典文章。

其中关于包装sikuli的基本函数如下：

9 
10 # =============================================== #
11 #          SikuliWrapperOverwritten sikuli methods             #
12 # =============================================== #
13 
14 # function for calling native sikuli methods
15 def sikuli_method(name, *args, **kwargs):
16     return sys.modules['sikuli.Sikuli'].__dict__[name](*args, **kwargs)
17 
18 # overwritten Screen.exists method
19 def exists(target, timeout=None):
20     addFoundImage(getFilename(target))
21     return sikuli_method('exists', target, timeout)

然后使用如下的Robotframework的Test Case：

*Setting*	*Value*	*Value*	*Value*
Library	SikuliWrapper	WITH NAME	wrapper
Test Timeout	10 minutes
*Variable*	*Value*	*Value*	*Value*
*Test Case*	*Action*	*Argument*	*Argument*
Test Sikuli	Exists	c:\\a.jpg	5
*Keyword*	*Action*	*Argument*	*Argument*	*Argument*

在执行后报错：
TypeError: exists(): 2nd arg can't be coerced to double

经过很多次尝试后，我发现是由于Robotframework的Test Case中数字“5”其实是个String，在输入

exists函数的时候没有转型成为int或者double。解决方法，改变exists函数如下： 

18 # overwritten Screen.exists method
19 def exists(target, timeout=None):
20     addFoundImage(getFilename(target))
21     return sikuli_method('exists', target, int(timeout))