ModuleNotFoundError when running model-checker with example on macOS

[benbrastmckie]

Bug Description

When running model-checker with no arguments and selecting to test an example, the program crashes with a ModuleNotFoundError.

Environment

• OS: macOS (Darwin 24.6.0)
• Python: 3.13
• model-checker version: 1.1.0
• Installation method: pip3 install model-checker

Steps to Reproduce

1. Install model-checker: pip3 install model-checker
2. Run: model-checker (with no arguments)
3. When prompted "Would you like to test an example in your project? (y/n):", enter: y

Expected Behavior

The example should run successfully or provide clear guidance on proper usage.

Actual Behavior

The program crashes with the following error:

Running example: /Users/nicky/Documents/project_test/examples.py
Traceback (most recent call last):
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/builder/loader.py", line 556, in _load_as_package_module
    module = importlib.import_module(full_module_name)
  File "/usr/local/Cellar/python@3.13/3.13.7/Frameworks/Python.framework/Versions/3.13/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1310, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1324, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'project_test'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/nicky/Library/Python/3.13/bin/model-checker", line 7, in <module>
    sys.exit(run())
             ~~~^^
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/__main__.py", line 266, in run
    main()
    ~~~~^^
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/__main__.py", line 254, in main
    module = BuildModule(module_flags)
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/builder/module.py", line 64, in __init__
    self._load_module()
    ~~~~~~~~~~~~~~~~~^^
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/builder/module.py", line 90, in _load_module
    self.module = self.loader.load_module()
                  ~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/builder/loader.py", line 270, in load_module
    return self._load_as_package_module()
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/Users/nicky/Library/Python/3.13/lib/python/site-packages/model_checker/builder/loader.py", line 568, in _load_as_package_module
    raise ImportError(
    ...<2 lines>...
    )
ImportError: Failed to import project_test.examples from package project_test. Make sure all relative imports are correct. Original error: No module named 'project_test'

Error running example: Command '['model-checker', '/Users/nicky/Documents/project_test/examples.py']' returned non-zero exit status 1.
You can run it manually with: model-checker /Users/nicky/Documents/project_test/examples.py

Additional Context

The issue appears to be that the example tries to import from a non-existent project_test module when it should either:

1. Create the necessary project structure first
2. Use a standalone example that doesn't require a package structure
3. Provide clearer instructions on the expected project setup