import pytest
from module_under_test import function_to_test


@pytest.fixture
def sample_data():
    """Provide shared test data."""
    return {"key": "value"}


class TestFunctionName:
    """Tests for function_name."""

    def test_happy_path(self, sample_data):
        result = function_to_test(valid_input)
        assert result == expected_output

    def test_empty_input(self):
        result = function_to_test("")
        assert result == expected_for_empty

    @pytest.mark.parametrize("input_val,expected", [
        ("valid", True),
        ("", False),
        (None, False),
    ])
    def test_various_inputs(self, input_val, expected):
        assert function_to_test(input_val) == expected