custom_formatting.py

import re
import unittest

FORMAT = {
    "b": lambda r: r["brand"],
    "m": lambda r: r["model"],
    "y": lambda r: str(r["year"])[2:],
    "Y": lambda r: r["year"],
    "%": lambda r: "%"
}
__format = format

def format_result(result, format):
    """
    Format values according to a certain format specification:
        %b = Brand
        %m = Model
        %y = Year (YY)
        %Y = Year (YYYY)
    """
    return re.compile("%(.)").sub(lambda m: FORMAT[m.group(1)](result), format)


class FormatResultTestCase(unittest.TestCase):
    def setUp(self):
        self.result = {
            'brand': 'Ford',
            'model': 'Fiesta',
            'year': '1996'
        }

    def test_format_result_case_1(self):
        """Should format it ok with characters surrounding format"""
        self.assertEqual(
            format_result(self.result, "(%b) - %m"),
            "(Ford) - Fiesta"
        )

    def test_format_result_case_2(self):
        """Should format ok without chars surrounding"""
        self.assertEqual(
            format_result(self.result, "%b - %m"),
            "Ford - Fiesta"
        )

    def test_format_result_case_3(self):
        """Should format ok other random chars"""
        self.assertEqual(
            format_result(self.result, "Brand: %b - Model: %m"),
            "Brand: Ford - Model: Fiesta"
        )

    def test_format_result_surrounded_with_quotes(self):
        """Should format ok if a format is quoted"""
        self.assertEqual(
            format_result(self.result, "Brand: '%b' - Model: '%m'"),
            "Brand: 'Ford' - Model: 'Fiesta'"
        )

    def test_format_with_full_year(self):
        """Should format ok with YYYY year"""
        self.assertEqual(
            format_result(self.result, "Brand: %b - Model: %m - Year: %Y"),
            "Brand: Ford - Model: Fiesta - Year: 1996"
        )

    def test_format_with_two_digits_year(self):
        """Should format ok with YY year"""
        self.assertEqual(
            format_result(self.result, "Brand: %b - Model: %m - Year: %y"),
            "Brand: Ford - Model: Fiesta - Year: 96"
        )


if __name__ == '__main__':
    unittest.main()