def test_reverse_4():
    assert t.reverse_string('hello') == 'olleh'
def test_reverse_3():
    assert t.reverse_string("mississippi") == "ippississim"
def test_reverse_5():
    assert t.reverse_string('xyz') == 'zyx'
def test_reverse_2():
    assert t.reverse_string('x') == 'x'
def test_reverse_1():
    assert t.reverse_string("moxie") == "eixom"
def test_empty():
    assert t.reverse_string('') == ''