def test_special():
counts = CharacterCounter("a! b")
assert counts.get_count('!') == 1
def test_empty():
counts = CharacterCounter("")
assert counts.get_count('a') == 0
assert counts.get_count('C') == 0
assert counts.get_count('z') == 0
def test_single_zero():
counts = CharacterCounter("c")
assert counts.get_count('d') == 0
def test_upper_in_lower_get():
counts = CharacterCounter("F")
assert counts.get_count('f') == 1
def test_single():
counts = CharacterCounter("c")
assert counts.get_count('c') == 1