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Infinite loop, input, continue and break

Pybites

Level: Intro (score: 1)

In this Bite we'll get you to take user input using the input builtin and see if it matches items within a list.

In the while loop ask the user to enter a color and capture that input.

Check to see whether they've entered 'quit'. If so, print bye and exit (break) the loop, effectively ending the function.

If not, check to see whether the color (input) is in the VALID_COLORS color list. If it is, then print the color in lower case. If not, print Not a valid color and continue the loop. Then conclude by printing bye.

For this exercise the tests check standard output (what you print) so it's important to not print anything else (e.g. a string asking the user to enter a color), nor invoke the print_colors() function at the bottom of your code. It will fail the tests.

As you want to ask the user over and over again till they quit, you can use an infinite while loop. We already provided that in the template code, just code inside that loop.

Code
Tests

from unittest.mock import patch

from colors import print_colors

NOT_VALID = 'Not a valid color'

def call_print_colors():
    # some people prefer sys.exit instead of break
    try:
        print_colors()
    except SystemExit:
        pass

@patch("builtins.input", side_effect=['quit'])
def test_straight_quit(input_mock, capsys):
    # user only enter quit, program prints bye and breaks loop
    call_print_colors()
    actual = capsys.readouterr()[0].strip()
    expected = 'bye'
    assert actual == expected

@patch("builtins.input", side_effect=['blue', 'quit'])
def test_one_valid_color_then_quit(input_mock, capsys):
    # user enters blue = valid color so print it
    # then user enters quit so break out of loop = end program
    call_print_colors()
    actual = capsys.readouterr()[0].strip()
    expected = 'blue\nbye'
    assert actual == expected

@patch("builtins.input", side_effect=['Blue', 'quit'])
def test_title_cased_color_is_fine_too(input_mock, capsys):
    # user enters Blue = valid color, program needs to lowercase it
    # then user enters quit so break out of loop = end program
    call_print_colors()
    actual = capsys.readouterr()[0].strip()
    expected = 'blue\nbye'
    assert actual == expected

@patch("builtins.input", side_effect=['green', 'quit'])
def test_one_invalid_color_then_quit(input_mock, capsys):
    # user enters green which is not in VALID_COLORS so continue the loop,
    # user then enters quit so loop breaks (end function / program)
    call_print_colors()
    actual = capsys.readouterr()[0].strip()
    expected = f'{NOT_VALID}\nbye'
    assert actual == expected

@patch("builtins.input", side_effect=['white', 'red', 'quit'])
def test_invalid_then_valid_color_then_quit(nput_mock, capsys):
    # white is not a valid color so continue the loop,
    # then user enters red which is valid so print it, then quit
    call_print_colors()
    actual = capsys.readouterr()[0].strip()
    expected = f'{NOT_VALID}\nred\nbye'
    assert actual == expected

@patch("builtins.input", side_effect=['yellow', 'orange', 'quit'])
def test_valid_then_invalid_color_then_quit(input_mock, capsys):
    # yellow is a valid color so print it, user then enters orange
    # which is not a valid color so continue loop, lastly user
    # enters quit so exit loop = reaching end function / program
    call_print_colors()
    actual = capsys.readouterr()[0].strip()
    expected = f'yellow\n{NOT_VALID}\nbye'
    assert actual == expected