import pytest
import os
import sys
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
from functions.string_utils import *
import warnings

def test_uppercase_normal():
    # Normal string uppercase conversion
    assert uppercase("hello") == "HELLO"

def test_uppercase_type_error():
    # Raises TypeError when input is None (invalid input)
    with pytest.raises(TypeError):
        uppercase(None)

def test_reverse_string():
    # Tests string reversal correctness
    assert reverse("abc") == "cba"

def test_warning_emit():
    # Emits a Python UserWarning, checks warning capture
    warnings.warn("Test warning", UserWarning)

def test_unicode_encode_error():
    # UnicodeEncodeError due to decoding malformed surrogate byte
    with pytest.raises(UnicodeEncodeError):
        b'\udc80'.decode('utf-8')

def test_unicode_decode_error():
    # UnicodeDecodeError when decoding invalid byte sequence
    with pytest.raises(UnicodeDecodeError):
        b'\xff'.decode('utf-8')

def test_unicode_decode_surrogateescape():
    # UnicodeDecodeError with strict error handler on invalid byte
    with pytest.raises(UnicodeDecodeError):
        b"\x80".decode("utf-8", errors="strict")

def test_import_warning():
    # Capture and check ImportWarning emitted
    with warnings.catch_warnings(record=True) as w:
        warnings.simplefilter("always")
        warnings.warn("Import warning", ImportWarning)
        assert any(item.category == ImportWarning for item in w)

@pytest.mark.xfail(reason="Expected failure: uppercase does not handle digits")
def test_xfail_uppercase_digits():
    # Expected fail test because uppercase won't change digits
    assert uppercase("abc123") == "ABC1234"

def test_keyboard_interrupt_direct():
    # Directly raise KeyboardInterrupt exception
    raise KeyboardInterrupt()