py.test 由于缺少模块而失败

Question

我想写一个测试，但是这个测试只有安装了nlopt模块才能通过。由于此模块是 可选的 ，我想知道是否有一种方法可以编写不会阻止 py.test 在模块不存在时完全失败的测试。此时，py.test 停止，因为它找不到 nlopt 模块：

$ make test
py.test --exitfirst tests/
============================================================= test session starts =============================================================
platform darwin -- Python 3.4.2 -- py-1.4.26 -- pytest-2.6.4
collecting 0 items / 1 errors
=================================================================== ERRORS ====================================================================
_____________________________________________ ERROR collecting tests/unit/fem/test_simulation.py ______________________________________________
tests/unit/fem/test_simulation.py:5: in <module>
    from hybrida.fem import Simulation, Step, Eigenvalue
src/hybrida/__init__.py:4: in <module>
    from . import geometry
src/hybrida/geometry/__init__.py:3: in <module>
    from . import distance
src/hybrida/geometry/distance.py:9: in <module>
    import nlopt
E   ImportError: No module named 'nlopt'
--------------------------------------------------------------- Captured stdout ---------------------------------------------------------------
 nlopt does not seem to be installed. 
=========================================================== short test summary info ===========================================================
ERROR tests/unit/fem/test_simulation.py
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
=========================================================== 1 error in 0.67 seconds ===========================================================
make: *** [test] Error 2

我试图在测试文件的开头添加一个 try-except 块，但这没有帮助：

try:
    import nlopt
    import numpy as np

except ImportError:
    print("""nlopt does not seem to be installed""")

nlopt 模块在我正在为其编写测试的库中使用。目前，如果找不到模块，库会引发异常。在使用模块的文件的顶层：

try:
    import nlopt

except ImportError:
    print("""3[91m nlopt does not seem to be installed. Please install it by downloading nlopt, and installing it using
        $ ./configure --enable-shared
        $ make
        $ make install
        and adding /usr/local/lib/Python3.4/site-packages to the PYTHONPATH
        (or wherever nlopt has been installed):
        export PYTHONPATH=$PYTHONPATH:/usr/local/lib/Python3.4/site-packages

        Note: although Homebrew provides nlopt, it does not install the Python interface.3[0m""")
    raise

Answer 1

使用conditional import machinerypytest提供：

nlopt = pytest.importorskip('nlopt')

将该行放在使用 nlopt 的特定测试函数中（或在一组函数的设置方法中），它只会在无法导入时跳过那些。

py.test 由于缺少模块而失败

py.test fails due to missing module

python

pytest