romantest.py

"""Unit test for roman.py

This program is part of "Dive Into Python", a free Python book for
experienced programmers.  Visit http://diveintopython.org/ for the
latest version.
"""

__author__ = "Mark Pilgrim (mark@diveintopython.org)"
__version__ = "$Revision: 1.2 $"
__date__ = "$Date: 2004/05/05 21:57:19 $"
__copyright__ = "Copyright (c) 2001 Mark Pilgrim"
__license__ = "Python"

import roman                                                                # the module to be tested
import unittest

class KnownValues(unittest.TestCase):
	knownValues = ( (1, 'I'),
					(2, 'II'),
					(3, 'III'),
					(4, 'IV'),
					(5, 'V'),
					(6, 'VI'),
					(7, 'VII'),
					(8, 'VIII'),
					(9, 'IX'),
					(10, 'X'),
					(50, 'L'),
					(100, 'C'),
					(500, 'D'),
					(1000, 'M'),
					(31, 'XXXI'),
					(148, 'CXLVIII'),
					(294, 'CCXCIV'),
					(312, 'CCCXII'),
					(421, 'CDXXI'),
					(528, 'DXXVIII'),
					(621, 'DCXXI'),
					(782, 'DCCLXXXII'),
					(870, 'DCCCLXX'),
					(941, 'CMXLI'),
					(1043, 'MXLIII'),
					(1110, 'MCX'),
					(1226, 'MCCXXVI'),
					(1301, 'MCCCI'),
					(1485, 'MCDLXXXV'),
					(1509, 'MDIX'),
					(1607, 'MDCVII'),
					(1754, 'MDCCLIV'),
					(1832, 'MDCCCXXXII'),
					(1993, 'MCMXCIII'),
					(2074, 'MMLXXIV'),
					(2152, 'MMCLII'),
					(2212, 'MMCCXII'),
					(2343, 'MMCCCXLIII'),
					(2499, 'MMCDXCIX'),
					(2574, 'MMDLXXIV'),
					(2646, 'MMDCXLVI'),
					(2723, 'MMDCCXXIII'),
					(2892, 'MMDCCCXCII'),
					(2975, 'MMCMLXXV'),
					(3051, 'MMMLI'),
					(3185, 'MMMCLXXXV'),
					(3250, 'MMMCCL'),
					(3313, 'MMMCCCXIII'),
					(3408, 'MMMCDVIII'),
					(3501, 'MMMDI'),
					(3610, 'MMMDCX'),
					(3743, 'MMMDCCXLIII'),
					(3844, 'MMMDCCCXLIV'),
					(3888, 'MMMDCCCLXXXVIII'),
					(3940, 'MMMCMXL'),
					(3999, 'MMMCMXCIX'),
					(4000, 'MMMM'),                                 # I thought numerals > 3999 were illegal!? (13.1)
					(4500, 'MMMMD'),                                # hmmmmm these values are not in section 13.3...        
					(4888, 'MMMMDCCCLXXXVIII'),                     # 15.2: oh, "customer requirements" changed
					(4999, 'MMMMCMXCIX'))

	def testToRomanKnownValues(self):                               # 13.4: each test is its own method, which must take no parameters and return no value
		"""toRoman should give known result with known input"""     # the test is considered passed iff no exception is raised
		for integer, numeral in self.knownValues:
			result = roman.toRoman(integer)
			self.assertEqual(numeral, result)

	def testFromRomanKnownValues(self):                             # 13.5 (implicitly)
		"""fromRoman should give known result with known input"""
		for integer, numeral in self.knownValues:
			result = roman.fromRoman(numeral)
			self.assertEqual(integer, result)                       # refer to the OTHER half of the 2-tuple

class ToRomanBadInput(unittest.TestCase):                               # 13.5: Testing for failure
	def testTooLarge(self):
		"""toRoman should fail with large input"""
		self.assertRaises(roman.OutOfRangeError, roman.toRoman, 5000)   # this should raise! easier than a manual try-except
                                                                        # - 15.2: increased from 4000 to 5000
	def testZero(self):
		"""toRoman should fail with 0 input"""
		self.assertRaises(roman.OutOfRangeError, roman.toRoman, 0)

	def testNegative(self):
		"""toRoman should fail with negative input"""
		self.assertRaises(roman.OutOfRangeError, roman.toRoman, -1)

	def testDecimal(self):
		"""toRoman should fail with non-integer input"""
		self.assertRaises(roman.NotIntegerError, roman.toRoman, 0.5)

class FromRomanBadInput(unittest.TestCase):
	def testTooManyRepeatedNumerals(self):
		"""fromRoman should fail with too many repeated numerals"""
		for s in ('MMMMM', 'DD', 'CCCC', 'LL', 'XXXX', 'VV', 'IIII'):               # 15.2: changed from 'MMMM' to 'MMMMM" to reflect new customer requirements
			self.assertRaises(roman.InvalidRomanNumeralError, roman.fromRoman, s)   # 13.5: custom exception 3 of 3

	def testRepeatedPairs(self):
		"""fromRoman should fail with repeated pairs of numerals"""
		for s in ('CMCM', 'CDCD', 'XCXC', 'XLXL', 'IXIX', 'IVIV'):
			self.assertRaises(roman.InvalidRomanNumeralError, roman.fromRoman, s)

	def testMalformedAntecedent(self):
		"""fromRoman should fail with malformed antecedents"""
		for s in ('IIMXCC', 'VX', 'DCM', 'CMM', 'IXIV',
				  'MCMC', 'XCX', 'IVI', 'LM', 'LD', 'LC'):
			self.assertRaises(roman.InvalidRomanNumeralError, roman.fromRoman, s)

	def testBlank(self):                                            # 15.1: Handling bugs        
		"""fromRoman should fail with blank string"""
		self.assertRaises(roman.InvalidRomanNumeralError, roman.fromRoman, "")

class SanityCheck(unittest.TestCase):                               # 13.6: Testing for sanity            
	def testSanity(self):
		"""fromRoman(toRoman(n))==n for all n"""
		for integer in range(1, 5000):                              # 15.2: upper limit increased from 4000 to 5000 to reflect new customer requirements    
			numeral = roman.toRoman(integer)
			result = roman.fromRoman(numeral)
			self.assertEqual(integer, result)

class CaseCheck(unittest.TestCase):
	def testToRomanCase(self):
		"""toRoman should always return uppercase"""
		for integer in range(1, 5000):
			numeral = roman.toRoman(integer)
			self.assertEqual(numeral, numeral.upper())              # not testing correctness or consistency, JUST capitalization
                                                                    # "each test case should only answer a single question"
	def testFromRomanCase(self):
		"""fromRoman should only accept uppercase input"""
		for integer in range(1, 5000):
			numeral = roman.toRoman(integer)
			roman.fromRoman(numeral.upper())                        # assume nothing about toRoman() in the fromRoman() test!
                                                                    # also, this is an implicit test that this line does NOT raise
			self.assertRaises(roman.InvalidRomanNumeralError, 
							  roman.fromRoman, numeral.lower())

if __name__ == "__main__":
	unittest.main()                                                 # 14.1: runs each method in each class defined in romantest.py
                                                                    # failure = failed assertion; error = "unexpected" exception