python的导入器和ModuleNotFoundError

Question

我的系统似乎无法从其他文件夹访问模块。例如，如果我将我的目录设置为

~/Downloads/principles_of_programming/object-oriented-programming/fibonacci 

跑

pytest tests/test_fibonacci.py

我明白了

==================================================== test session starts ===================================================== 
platform win32 -- Python 3.9.1, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
rootdir: C:\Users\Ryan\Downloads\principles_of_programming\object-oriented-programming, configfile: setup.cfg
collected 0 items                                                                                                              

=================================================== no tests ran in 0.05s ==================================================== 
ERROR: file or directory not found: tests/test_fibonacci.py

如果我将目录更改为

~/Downloads/principles_of_programming/object-oriented-programming

然后按照上面的方法运行测试

==================================================== test session starts ===================================================== 
platform win32 -- Python 3.9.1, pytest-6.2.2, py-1.10.0, pluggy-0.13.1
rootdir: C:\Users\Ryan\Downloads\principles_of_programming\object-oriented-programming, configfile: setup.cfg
collected 0 items / 1 error                                                                                                    

=========================================================== ERRORS =========================================================== 
__________________________________________ ERROR collecting tests/test_fibonacci.py __________________________________________ 
ImportError while importing test module 'C:\Users\Ryan\Downloads\principles_of_programming\object-oriented-programming\tests\test_fibonacci.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
..\..\..\AppData\Local\Programs\Python\Python39\lib\importlib\__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests\test_fibonacci.py:1: in <module>
    from fibonacci import fib
E   ModuleNotFoundError: No module named 'fibonacci'
================================================== short test summary info =================================================== 
ERROR tests/test_fibonacci.py
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 
====================================================== 1 error in 0.45s ====================================================== 

Error Output

Answer 1

在处理“import”子句时，Python将首先检查它是否在安装文件夹中，或者是否安装了包，如果失败，则搜索当前工作目录，并考虑相对路径

例如import tests.test_fibonacci表示当前工作目录中有一个名为tests的文件夹，脚本test_fibonacci.py在其中，python将从名称空间“tests.test\u fibonacci”的第一行到最后一行运行它