ImportError: No module named 'Shapes' when running Python scripts and tests

Question

Description:

• I'm encountering an ImportError issue in my Python project related to module imports. The project structure is as follows:

C:.
├───Shapes
│   │   Circle.py
│   │   Rectangle.py
│   │   Shape.py
│   │   __init__.py
│           
├───tests
│   │   conftest.py
│   │   test_circle.py
│   │   test_rectangle.py

• In Circle.py and Rectangle.py, I'm getting the error "No module named 'Shapes'" when trying to run the scripts. Additionally, when attempting to run tests in the tests directory, I encounter the error: "ModuleNotFoundError: No module named 'Shapes'".

# Circle.py
from Shapes.Shape import Shape  # Importing the Shape base class
import math as Math

class Circle(Shape):
    def __init__(self, radius=0):
        self.radius = radius

    @property
    def radius(self):
        return self._radius

    @radius.setter
    def radius(self, radius):
        self._radius = max(1, radius)

    def area(self):
        return Math.pi * Math.pow(self.radius, 2)

# ... (rest of the code)

# Rectangle.py
from Shapes.Shape import Shape  # Importing the Shape base class

class Rectangle(Shape):
    def __init__(self, width, height):
        self.width = width
        self.height = height

    @property
    def width(self):
        return self._width

    @property
    def height(self):
        return self._height

    @width.setter
    def width(self, width):
        self._width = width

    @height.setter
    def height(self, height):
        self._height = height

    def area(self):
        return self.height * self.width

# ... (rest of the code)

# test_circle.py
import pytest
from Shapes.Circle import Circle
import math as Math

class TestCircle:
    def setup_method(self, method):
        # Setting up the test environment
        self.circle = Circle(2)

    def teardown_method(self, method):
        # Tearing down the test environment
        pass

    def test_radius(self):
        assert self.circle.radius == 2

    def test_area(self):
        assert self.circle.area() == Math.pi * Math.pow(self.circle.radius, 2)

# test_rectangle.py
import pytest
from Shapes.Rectangle import Rectangle

def test_area():
    assert object.area() == 6  # Assuming object is an instance of Rectangle with width=2 and height=3

Error Messages:

• When running Circle.py or Rectangle.py, I get the error:

No module named 'Shapes'

• When running tests in the tests directory, I encounter:

ModuleNotFoundError: No module named 'Shapes'

Attempts to Resolve:

• I've tried adding the project root to the sys.path in the test files, but its not best practise and I'm looking for a cleaner solution.

• Using relative imports didn't resolve the issue just got.

Exception has occurred: ImportError
attempted relative import with no known parent package

Question:

• How can I fix the "No module named 'Shapes'" error in my Python project structure? Is there a recommended approach to organize the project and imports?

What I Tried:

Attempted to run Circle.py and Rectangle.py scripts and executed tests in the tests directory. Explored relative imports and considered adding the project root to sys.path.

Expected:

Scripts to run without ImportError for 'Shapes'. Tests to execute successfully without "No module named 'Shapes'" error.

Actual Result:

Received ImportError for 'Shapes' when running scripts and ModuleNotFoundError in tests.

Answer 1

It looks like I found the solution to the issue I was facing. The problem arises when running tests directly from the terminal using

pytest tests/ 

or

python pytest tests/

In these cases, pytest treats the tests/ directory as the root of the project, leading to import errors.

To resolve this, I discovered that running tests as a module with

python -m pytest tests/ 

Solves the problem. By using -m, I explicitly indicate that tests is a module, and now the import paths are handled correctly.