pytest与另一个版本的python一起运行

问题描述

我已经安装了pyenv，并安装了不同版本的python:

I've installed pyenv and have different versions of python installed with it:

$ pyenv versions
  system
  2.7.1
  3.2.5
  3.5.0
  3.5.1
* 3.5.2

我使用以下命令切换到python 3.5.2:

I use the following command to switch to python 3.5.2:

当我检查python版本时，这就是我得到的:

And when I check the python version this is what I get:

$ python --version
Python 3.5.2

但是当我运行pytest时，它仍然在python 2.7.6下运行:

But when I run pytest, it still runs under python 2.7.6:

为什么pytest在旧版本下运行?

Why is pytest running under the older version?

推荐答案

底线:运行

• python -m pytest或
• py.test-<version>(如果您的替代Python和pytest已与系统软件包管理器一起安装)，或者
• 如果您的替代Python已安装pyenv，请使用pyenv切换到该版本 ，并确保已为其安装pytest.然后，您可以运行pytest.
  • 由于pip可执行文件也是要切换的可执行文件之一，因此，在安装 pytest之前，还需要切换到其他Python .
  • python -m pytest, or
  • py.test-<version> if your alternative Python and pytest are installed with system package manager, or
  • if your alternative Python has been installed with pyenv, switch with pyenv to that version and make sure you have pytest installed for it. Then you can just run pytest.
    • since the pip executable is also among the ones being switched, you need to switch to the alternative Python before installing pytest for it, too.

    如我所见，/usr/bin/pytest(属于系统软件包管理器的python-pytest软件包)具有shebang !#/usr/bin/python，因为它对应于系统python的安装.

    As I can see, /usr/bin/pytest (that belongs to the system package manager's python-pytest package) has a shebang !#/usr/bin/python since it corresponds to the system python's installation.

    pyenv，如其README.md所述，它不能代替/usr/bin/python- 因为它确实不应替换，以免破坏系统软件包..

    相反，它将目录添加到PATH并在其中插入启动器(称为" shim )，这是在您键入"python"时调用的内容.您可能已经猜到了，这种骇客会被上述的Shebang忽略-应当如此.

    Instead, it adds its directory to PATH and inserts a launcher there (called "shim") which is what gets invoked when you type "python". As you probably guessed, this hack is ignored by a shebang like the above - as it should.

    • 运行python -m pytest将使启动的任何python都使用其安装中的软件包.
    • 或者，对于其他Python版本，pytest可能会在名为py.test-<version>的PATH上包含版本化的可执行文件(例如，py.test-3或py.test-3.6)，具体取决于安装方式.
      • 如果它来自系统软件包管理器的非标准python软件包(例如python36-pytest)，则实际上可以保证.
      • 我检查了是否使用pip安装了一个版本，它只会创建一个未版本控制的可执行文件(尽管您可以自己创建一个版本控制的可执行文件).此外，如果为不同的Python版本安装相同的软件包但使用相同的--prefix，它将覆盖现有的可执行文件！
      • Running python -m pytest will make whichever python that launches itself use the package from its installation.
      • Alternatively, pytest for your other Python version may include versioned executables on the PATH named py.test-<version> (e.g. py.test-3 or py.test-3.6) depending on the way you installed it.
        • If it's from a system package manager's package for nonstandard python - like python36-pytest - this is virtually guaranteed.
        • I checked that if you install a version with pip, it only creates an unversioned executable (though you can create a versioned one yourself). Moreover, if you install the same package for a different Python version but with the same --prefix, it will overwrite the existing one's executable!
        • 这不适用于系统的Python，但可以使用默认的/usr/local.
        • 一旦您切换到其他Python版本，它就会声明为 shims 创建一个 shims em>该版本当前安装的所有脚本(包括pip !！)，因此，调用没有路径的脚本将运行那些补片.
          • 因此，如果未为替代版本安装软件包(及其脚本)，但为系统版本安装了软件包，则尝试运行其可执行文件将陷入" /usr/local，仅显示您现在看到的结果
          • This is not applicable for the system's Python but the default /usr/local can be used for it.
          • Once you switch to an alternative Python version, it claims to create shims for all scripts (including pip!) that are currently installed for that version, so invoking those scripts without a path would run those shims.
            • So, if a package (and thus its script) is not installed for the alternative version but installed for system version, trying to run its executable would "fall through" to /usr/local with just the result you're seeing now.

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