"""Tests for the utils module."""

import pytest
from test_package.utils import format_number, is_even, factorial


class TestUtils:
    """Test cases for utility functions."""
    
    def test_format_number_integer(self):
        """Test formatting integers."""
        assert format_number(42) == "42"
        assert format_number(-5) == "-5"
    
    def test_format_number_float(self):
        """Test formatting floats."""
        assert format_number(3.14159) == "3.14"
        assert format_number(3.14159, 3) == "3.142"
        assert format_number(2.0) == "2.00"
    
    def test_is_even(self):
        """Test even number detection."""
        assert is_even(2) is True
        assert is_even(4) is True
        assert is_even(1) is False
        assert is_even(3) is False
        assert is_even(0) is True
        assert is_even(-2) is True
        assert is_even(-1) is False
    
    def test_factorial_positive(self):
        """Test factorial of positive numbers."""
        assert factorial(0) == 1
        assert factorial(1) == 1
        assert factorial(5) == 120
        assert factorial(3) == 6
    
    def test_factorial_negative(self):
        """Test factorial of negative numbers raises error."""
        with pytest.raises(ValueError, match="Factorial is not defined for negative numbers"):
            factorial(-1)