./foo.py < 的 Pythonic 等价物酒吧.png [英] Pythonic equivalent of ./foo.py < bar.png

问题描述

我有一个从 sys.stdin 读取的 Python 程序，所以我可以用 ./foo.py < 调用它.bar.png.如何从另一个 Python 模块中测试此代码?也就是说，如何在运行测试脚本时将 stdin 设置为指向文件的内容?我不想做类似 ./test.py < 的事情.测试.png.我不认为我可以使用 fileinput，因为输入是二进制的，我只想处理一个文件.该文件使用来自 PIL.

I've got a Python program that reads from sys.stdin, so I can call it with ./foo.py < bar.png. How do I test this code from within another Python module? That is, how do I set stdin to point to the contents of a file while running the test script? I don't want to do something like ./test.py < test.png. I don't think I can use fileinput, because the input is binary, and I only want to handle a single file. The file is opened using Image.open(sys.stdin) from PIL.

推荐答案

除了用作独立程序之外，您还应该概括您的脚本，以便可以从测试脚本中调用它.这是执行此操作的示例脚本:

You should generalise your script so that it can be invoked from the test script, in addition to being used as a standalone program. Here's an example script that does this:

#! /usr/bin/python

import sys

def read_input_from(file):
    print file.read(),

if __name__ == "__main__":
    if len(sys.argv) > 1:
        # filename supplied, so read input from that
        filename = sys.argv[1]
        file = open(filename)
    else:
        # no filename supplied, so read from stdin
        file = sys.stdin
    read_input_from(file)

如果使用文件名调用它，将显示该文件的内容.否则，将显示从 stdin 读取的输入.(能够在命令行上传递文件名可能对您的 foo.py 脚本很有用.)

If this is called with a filename, the contents of that file will be displayed. Otherwise, input read from stdin will be displayed. (Being able to pass a filename on the command line might be a useful improvement for your foo.py script.)

在测试脚本中，您现在可以使用文件调用 foo.py 中的函数，例如:

In the test script you can now invoke the function in foo.py with a file, for example:

#! /usr/bin/python

import foo

file = open("testfile", "rb")
foo.read_input_from(file)

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