Pytest unit testing getting a Can't instantiate abstract class error

I'm currently testing this code using pytest from Storm_Centre.py

class Storm_Centre:
    def __init__(self):
        self.storm_list = []
        
    def already_exists(self, name) -> bool:
        for storm in self.storm_list:
            if storm.name == name:
                return True
        return False

this code uses code from Storm.py

from abc import ABC, abstractmethod


class Storm(ABC):
    def __init__(self, name, wind_speed):
        self.name = name
        self.wind_speed = wind_speed
        super().__init__()

    @abstractmethod
    def calculate_classification(self):
        pass

    @abstractmethod
    def get_advice(self):
        pass

I'm testing the code in test_storm.py using the following code:

import pytest
from Storm import Storm
from Storm_Centre import Storm_Centre

def test_already_exists():
    s1 = Storm('Jeff', 10)
    c1 = Storm_Centre()
    c1.storm_list.append(s1)
    assert(c1.already_exists('Jeff') == True)
    assert(c1.already_exists('Dave') == False)

When running the test I get a "Can't instantiate abstract class" error. If anyone could help solve this error it would be much appreciated. thank you!

The point of creating an Abstract Class is that it's a class that you never instantiate. Instead, you have to implement a non-abstract subclass of it, which implements the two abstract methods, and then that's what you instantiate.

When you're writing the unit tests for Storm_Centre and the abstract Storm class itself, you'll need to define a non-abstract test sub class, something like this:

import pytest
from storm import Storm
from storm_centre import Storm_Centre

class TestStorm(Storm):
    def calculate_classification(self):
        return 4.2
    def get_advice(self):
        return "don't panic"

def test_already_exists():
    s1 = TestStorm('Jeff', 10)
    c1 = Storm_Centre()
    c1.storm_list.append(s1)
    assert(c1.already_exists('Jeff') == True)
    assert(c1.already_exists('Dave') == False)

EDIT: removed the unnecessary __init__ method.

PS: you can use @chepner's idea to make this even smaller:

class TestStorm(Storm):
    pass
TestStorm.__abstractmethods__ = frozenset()

PPS: the typical Python filename convention is to use lowercase: class Storm is normally defined in file storm.py.

Abstract base classes are fairly easy to "subvert" for testing purposes.

>>> Storm.__abstractmethods__
frozenset({'calculate_classification', 'get_advice'})
>>> Storm("Jeff", 10)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Can't instantiate abstract class Storm with abstract methods calculate_classification, get_advice
>>> Storm.__abstractmethods__ = frozenset()
>>> Storm("Jeff", 10)
<__main__.Storm object at 0x1011d0f50>

So to avoid the need to define a concrete subclass to instantiate, you can simply set the __abstractmethods__ attribute to an empty list, set, etc, and the attempt to instantiate it will succeed (because it no longer reports any methods that must be overriden first).