Structuring your project guide leads to a ModuleNotFoundError in the tests module

Following this section, adding from .context import sample in my tests module gives me the following error: ModuleNotFoundError: No module named '__main__.context'; '__main__' is not a package

I was able to fix it by removing the . from from .context import sample, but I suspect that's not the ideal solution. I know that the from .context import sample is a relative import statement as described in PEP 328, but I just do not understand modules, packages, absolute and relative imports, etc. enough to say what's going on here.

I tried creating ./__init__.py and ./tests/__init__.py files, but that did not help.

Finally, I tried the following:

~> git clone git@github.com:navdeep-G/samplemod.git
~> python3 samplemod/tests/test_basic.py
Traceback (most recent call last):
  File "samplemod/tests/test_basic.py", line 3, in <module>
    from .context import sample
ModuleNotFoundError: No module named '__main__.context'; '__main__' is not a package

I'm not alone in hitting this issue. @rileyweber13 originally reported this problem a year ago.

从链接的“Test Suite”部分开始，并使用 samplemod/tests/test_basic.py 重现报告中的命令。跟踪测试文件的调用方式以及其相对导入的解析方式，然后更新指南，使文档中说明的设置和执行路径能够正常工作，且不会出现报告中的 ModuleNotFoundError。