Python - Testing and Debugging(lines, intersection, unittest module, TestCase class, main method)

Practical Programming
An Introduction to Computer Science
Using Python 3
(Pragmatic Programmers)
(Pragmatic Bookshelf)
Paul Gries (著) Jennifer Campbell (著)
Jason Montojo (著) Lynn Beighley (編集)

開発環境

• OS X Yosemite - Apple (OS)
• Emacs (CUI)、BBEdit - Bare Bones Software, Inc. (GUI) (Text Editor)
• Python 3.4 (プログラミング言語)

Practical Programming: An Introduction to Computer Science Using Python 3 (Pragmatic Programmers) (Paul Gries (著)、Jennifer Campbell (著)、Jason Montojo (著)、Lynn Beighley (編集)、Pragmatic Bookshelf)のChapter 15(Testing and Debugging)、15.7(Exercises) 2.を解いてみる。

15.7(Exercises) 2.

コード(BBEdit)

sample2.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import unittest

def lineIntersect(line1, line2):
    p1, p2 = line1
    p3, p4 = line2
    p1x, p1y = p1
    p2x, p2y = p2
    p3x, p3y = p3
    p4x, p4y = p4
    x1 = p2x - p1x
    y1 = p2y - p1y
    x2 = p4x - p3x
    y2 = p4y - p3y
    if x1 == 0:
        a1 = None
    else:
        a1 = y1 / x1
    if x2 == 0:
        a2 = None
    else:
        a2 = y2 / x2
    if a1 == None and a2 == None:
        if p1x == p3x:
            return line1
        else:
            return None
    if a1 == None:
        return [p1x, a2 * p1x + (p3y - a2 * p3x)]
    if a2 == None:
        return [a1 * p3x + (p1y - a1 * p1x), p3x]
    k1 = p1y - a1 * p1x
    k2 = p3y - a2 * p3x
    if a1 == a2:
        if k1 == k2:
            return line1
        else:
            return None
    x = (k2 - k1) / (a1 - a2)
    y = a1 * x + k1
    return [x, y]
            

class TestLineIntersect(unittest.TestCase):
    def test_not_intersect(self):
        line1 = [[0, 0], [1, 1]]
        line2 = [[0, 1], [1, 2]]
        expected = None
        actual = lineIntersect(line1, line2)
        self.assertEqual(expected, actual)
    def test_not_intersect1(self):
        line1 = [[0, 0], [1, 0]]
        line2 = [[0, 1], [1, 1]]
        expected = None
        actual = lineIntersect(line1, line2)
        self.assertEqual(expected, actual)
    def test_not_intersect2(self):
        line1 = [[0, 0], [0, 1]]
        line2 = [[1, 0], [1, 1]]
        expected = None
        actual = lineIntersect(line1, line2)
        self.assertEqual(expected, actual)
    def test_intersect(self):
        line1 = [[0, 0], [1, 1]]
        line2 = [[0, 1], [1, 0]]
        expected = [0.5, 0.5]
        actual = lineIntersect(line1, line2)
        self.assertEqual(expected, actual)
    def test_coincident(self):
        line1 = [[0, 0], [1, 1]]
        line2 = [[0, 0], [-1, -1]]
        expected = line1
        actual = lineIntersect(line1, line2)
        self.assertEqual(expected, actual)
    def test_coincident1(self):
        line1 = [[0, 0], [-1, -1]]
        line2 = [[0, 0], [1, 1]]
        expected = line1
        actual = lineIntersect(line1, line2)
        self.assertEqual(expected, actual)

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

入出力結果(Terminal, IPython)

$ ./sample2.py
......
----------------------------------------------------------------------
Ran 6 tests in 0.002s

OK
$