confusion on importing modules

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confusion on importing modules - carter187 - Mar-03-2024

Hello,

I want to build a simple web browser following along this https://browser.engineering/http.html and have created a directory like this:

webbrowser
    ---- __init__.py
    ---- src
         ---- __init__.py
         ---- URL
    ---- test
         ---- __init__.py
         ---- test_URL

according to 6.4 https://docs.python.org/3/tutorial/modules.html this is the way to import submodules but when I do

import unittest

import webbrowser.src.URL

class test_URL(unittest.TestCase):
	
	def test_init(self):
		test_URL = URL("http://www.example.org/index.html")
		test_URL.print_URL()
		assertEquals(1,1)

	if __name__ == '__main__':
	    unittest.main()

I get " No module named 'webbrowser.src'; 'webbrowser' is not a package ". I am using apple silicon M2 with mac os Sonoma if that is important.

RE: confusion on importing modules - Gribouillis - Mar-03-2024

webbrowser is a poor choice for the name of your package, because it is already the name of a module in Python's standard library. Try

import webbrowser
raise RuntimeError(webbrowser)

to see if Python imports the standard library's webbrowser or your webbrowser

RE: confusion on importing modules - carter187 - Mar-03-2024

thanks, I get

RuntimeError: <module 'webbrowser' from '/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/webbrowser.py'>

so it seems like the library module is imported. I changed webbrowser to Browser to run this

import unittest

import Browser.src.URL

class test_URL(unittest.TestCase):
	
	def test_init(self):
		test_URL = URL("http://www.example.org/index.html")
		test_URL.print_URL()
		assertEquals(1,1)

	if __name__ == '__main__':
	    unittest.main()

and I get

ModuleNotFoundError: No module named 'Browser'

RE: confusion on importing modules - Gribouillis - Mar-03-2024

(Mar-03-2024, 04:05 PM)carter187 Wrote: ModuleNotFoundError: No module named 'Browser'

As explained in the tutorial that you linked above, Python will find a package only if it is on the module search path. Concretely you can achieve this by adding the path to the parent directory of the Browser directory to the module search path. You could follow the reply that I made in this thread

Later you'll learn how to write pip-installable packages and install them in editable mode.

RE: confusion on importing modules - snippsat - Mar-03-2024

Can also advice to make a virtual environment(build into Python) then search path to folder will work.
Example setup.

myproject/
│
├── Browser/                 
│   ├── __init__.py                # Makes Browser a Python package
│   │
│   ├── src/                      
│   │   ├── __init__.py           
│   │   └── URL.py               
│   │
│   └── test/                      
│       ├── __init__.py          
│       └── test_URL.py           
│
└── other_project_files/           # Other project files (if any)

Start like this:

# Make
G:\env
λ python -m venv myproject

G:\env
λ cd myproject\

# In Linux source bin/activate
G:\env\myproject
λ G:\env\myproject\Scripts\activate

# Now working see (myproject) 
G:\env\myproject
(myproject) λ 

# Eg make folder folders/files from command line or use OS file explorer 
G:\env\myproject
(myproject) λ mkdir Browser

G:\env\myproject\Browser
(myproject) λ touch __init__.py
....

Test run.

G:\env\myproject\Browser\test                                                           
(myproject) λ rich test_URL.py                                                                                       
# Advice use pytest instead 
import unittest                                                                         
import Browser.src.URL                                                                  
                                                                                        
class test_URL(unittest.TestCase):                                                      
    def test_init(self):                                                                
        test_URL = "https://python-forum.io"                                            
        self.assertEqual(test_URL, Browser.src.URL.web_url())                           
                                                                                        
if __name__ == '__main__':                                                              
    unittest.main()                                                                     
                                                                                        
G:\env\myproject\Browser\test                                                           
(myproject) λ python test_URL.py                                                        
.                                                                                       
----------------------------------------------------------------------                  
Ran 1 test in 0.000s                                                                    
                                                                                        
OK                                                                                      
                                                                                        
G:\env\myproject\Browser\test                                                           
(myproject) λ