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python/exercises/practice/dominoes/dominoes_test.py
2021-02-01 19:08:02 -08:00

130 lines
4.7 KiB
Python

import unittest
from dominoes import (
can_chain,
)
# Tests adapted from `problem-specifications//canonical-data.json`
class DominoesTest(unittest.TestCase):
def test_empty_input_empty_output(self):
input_dominoes = []
output_chain = can_chain(input_dominoes)
self.assert_correct_chain(input_dominoes, output_chain)
def test_singleton_input_singleton_output(self):
input_dominoes = [(1, 1)]
output_chain = can_chain(input_dominoes)
self.assert_correct_chain(input_dominoes, output_chain)
def test_singleton_that_can_t_be_chained(self):
input_dominoes = [(1, 2)]
output_chain = can_chain(input_dominoes)
self.refute_correct_chain(input_dominoes, output_chain)
def test_three_elements(self):
input_dominoes = [(1, 2), (3, 1), (2, 3)]
output_chain = can_chain(input_dominoes)
self.assert_correct_chain(input_dominoes, output_chain)
def test_can_reverse_dominoes(self):
input_dominoes = [(1, 2), (1, 3), (2, 3)]
output_chain = can_chain(input_dominoes)
self.assert_correct_chain(input_dominoes, output_chain)
def test_can_t_be_chained(self):
input_dominoes = [(1, 2), (4, 1), (2, 3)]
output_chain = can_chain(input_dominoes)
self.refute_correct_chain(input_dominoes, output_chain)
def test_disconnected_simple(self):
input_dominoes = [(1, 1), (2, 2)]
output_chain = can_chain(input_dominoes)
self.refute_correct_chain(input_dominoes, output_chain)
def test_disconnected_double_loop(self):
input_dominoes = [(1, 2), (2, 1), (3, 4), (4, 3)]
output_chain = can_chain(input_dominoes)
self.refute_correct_chain(input_dominoes, output_chain)
def test_disconnected_single_isolated(self):
input_dominoes = [(1, 2), (2, 3), (3, 1), (4, 4)]
output_chain = can_chain(input_dominoes)
self.refute_correct_chain(input_dominoes, output_chain)
def test_need_backtrack(self):
input_dominoes = [(1, 2), (2, 3), (3, 1), (2, 4), (2, 4)]
output_chain = can_chain(input_dominoes)
self.assert_correct_chain(input_dominoes, output_chain)
def test_separate_loops(self):
input_dominoes = [(1, 2), (2, 3), (3, 1), (1, 1), (2, 2), (3, 3)]
output_chain = can_chain(input_dominoes)
self.assert_correct_chain(input_dominoes, output_chain)
def test_nine_elements(self):
input_dominoes = [
(1, 2),
(5, 3),
(3, 1),
(1, 2),
(2, 4),
(1, 6),
(2, 3),
(3, 4),
(5, 6),
]
output_chain = can_chain(input_dominoes)
self.assert_correct_chain(input_dominoes, output_chain)
# Utility methods
def normalize_dominoes(self, dominoes):
return list(sorted(tuple(sorted(domino)) for domino in dominoes))
def assert_same_dominoes(self, input_dominoes, output_chain):
msg = (
"Dominoes used in the output must be the same "
"as the ones given in the input"
)
input_normal = self.normalize_dominoes(input_dominoes)
output_normal = self.normalize_dominoes(output_chain)
self.assertEqual(input_normal, output_normal, msg)
def assert_consecutive_dominoes_match(self, output_chain):
for i in range(len(output_chain) - 1):
msg = (
"In chain {}, right end of domino {} ({}) "
"and left end of domino {} ({}) must match"
)
msg = msg.format(
output_chain, i, output_chain[i], i + 1, output_chain[i + 1]
)
self.assertEqual(output_chain[i][1], output_chain[i + 1][0], msg)
def assert_dominoes_at_ends_match(self, output_chain):
msg = (
"In chain {}, left end of first domino ({}) and "
"right end of last domino ({}) must match"
)
msg = msg.format(output_chain, output_chain[0], output_chain[-1])
self.assertEqual(output_chain[0][0], output_chain[-1][1], msg)
def assert_correct_chain(self, input_dominoes, output_chain):
msg = "There should be a chain for {}".format(input_dominoes)
self.assertIsNotNone(output_chain, msg)
self.assert_same_dominoes(input_dominoes, output_chain)
if not any(output_chain):
return
self.assert_consecutive_dominoes_match(output_chain)
self.assert_dominoes_at_ends_match(output_chain)
def refute_correct_chain(self, input_dominoes, output_chain):
msg = "There should be no valid chain for {}".format(input_dominoes)
self.assertIsNone(output_chain, msg)
if __name__ == "__main__":
unittest.main()