def test_to_lower_empty_input(self):
# Setup
input_text = ''
expected_output = ''
# Actual call
output_text = to_lower(input_text)
# Asserts
self.assertEqual(output_text, expected_output)
def test_to_lower_upper_input(self):
# Setup
input_text = 'HELLO'
expected_output = 'hello'
# Actual call
output_text = to_lower(input_text)
# Asserts
self.assertEqual(output_text, expected_output)