Commit | Line | Data |
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86530b38 AT |
1 | """Tests for binary operators on subtypes of built-in types.""" |
2 | ||
3 | import unittest | |
4 | from test import test_support | |
5 | ||
6 | def gcd(a, b): | |
7 | """Greatest common divisor using Euclid's algorithm.""" | |
8 | while a: | |
9 | a, b = b%a, a | |
10 | return b | |
11 | ||
12 | def isint(x): | |
13 | """Test whether an object is an instance of int or long.""" | |
14 | return isinstance(x, int) or isinstance(x, long) | |
15 | ||
16 | def isnum(x): | |
17 | """Test whether an object is an instance of a built-in numeric type.""" | |
18 | for T in int, long, float, complex: | |
19 | if isinstance(x, T): | |
20 | return 1 | |
21 | return 0 | |
22 | ||
23 | def isRat(x): | |
24 | """Test wheter an object is an instance of the Rat class.""" | |
25 | return isinstance(x, Rat) | |
26 | ||
27 | class Rat(object): | |
28 | ||
29 | """Rational number implemented as a normalized pair of longs.""" | |
30 | ||
31 | __slots__ = ['_Rat__num', '_Rat__den'] | |
32 | ||
33 | def __init__(self, num=0L, den=1L): | |
34 | """Constructor: Rat([num[, den]]). | |
35 | ||
36 | The arguments must be ints or longs, and default to (0, 1).""" | |
37 | if not isint(num): | |
38 | raise TypeError, "Rat numerator must be int or long (%r)" % num | |
39 | if not isint(den): | |
40 | raise TypeError, "Rat denominator must be int or long (%r)" % den | |
41 | # But the zero is always on | |
42 | if den == 0: | |
43 | raise ZeroDivisionError, "zero denominator" | |
44 | g = gcd(den, num) | |
45 | self.__num = long(num//g) | |
46 | self.__den = long(den//g) | |
47 | ||
48 | def _get_num(self): | |
49 | """Accessor function for read-only 'num' attribute of Rat.""" | |
50 | return self.__num | |
51 | num = property(_get_num, None) | |
52 | ||
53 | def _get_den(self): | |
54 | """Accessor function for read-only 'den' attribute of Rat.""" | |
55 | return self.__den | |
56 | den = property(_get_den, None) | |
57 | ||
58 | def __repr__(self): | |
59 | """Convert a Rat to an string resembling a Rat constructor call.""" | |
60 | return "Rat(%d, %d)" % (self.__num, self.__den) | |
61 | ||
62 | def __str__(self): | |
63 | """Convert a Rat to a string resembling a decimal numeric value.""" | |
64 | return str(float(self)) | |
65 | ||
66 | def __float__(self): | |
67 | """Convert a Rat to a float.""" | |
68 | return self.__num*1.0/self.__den | |
69 | ||
70 | def __int__(self): | |
71 | """Convert a Rat to an int; self.den must be 1.""" | |
72 | if self.__den == 1: | |
73 | try: | |
74 | return int(self.__num) | |
75 | except OverflowError: | |
76 | raise OverflowError, ("%s too large to convert to int" % | |
77 | repr(self)) | |
78 | raise ValueError, "can't convert %s to int" % repr(self) | |
79 | ||
80 | def __long__(self): | |
81 | """Convert a Rat to an long; self.den must be 1.""" | |
82 | if self.__den == 1: | |
83 | return long(self.__num) | |
84 | raise ValueError, "can't convert %s to long" % repr(self) | |
85 | ||
86 | def __add__(self, other): | |
87 | """Add two Rats, or a Rat and a number.""" | |
88 | if isint(other): | |
89 | other = Rat(other) | |
90 | if isRat(other): | |
91 | return Rat(self.__num*other.__den + other.__num*self.__den, | |
92 | self.__den*other.__den) | |
93 | if isnum(other): | |
94 | return float(self) + other | |
95 | return NotImplemented | |
96 | ||
97 | __radd__ = __add__ | |
98 | ||
99 | def __sub__(self, other): | |
100 | """Subtract two Rats, or a Rat and a number.""" | |
101 | if isint(other): | |
102 | other = Rat(other) | |
103 | if isRat(other): | |
104 | return Rat(self.__num*other.__den - other.__num*self.__den, | |
105 | self.__den*other.__den) | |
106 | if isnum(other): | |
107 | return float(self) - other | |
108 | return NotImplemented | |
109 | ||
110 | def __rsub__(self, other): | |
111 | """Subtract two Rats, or a Rat and a number (reversed args).""" | |
112 | if isint(other): | |
113 | other = Rat(other) | |
114 | if isRat(other): | |
115 | return Rat(other.__num*self.__den - self.__num*other.__den, | |
116 | self.__den*other.__den) | |
117 | if isnum(other): | |
118 | return other - float(self) | |
119 | return NotImplemented | |
120 | ||
121 | def __mul__(self, other): | |
122 | """Multiply two Rats, or a Rat and a number.""" | |
123 | if isRat(other): | |
124 | return Rat(self.__num*other.__num, self.__den*other.__den) | |
125 | if isint(other): | |
126 | return Rat(self.__num*other, self.__den) | |
127 | if isnum(other): | |
128 | return float(self)*other | |
129 | return NotImplemented | |
130 | ||
131 | __rmul__ = __mul__ | |
132 | ||
133 | def __truediv__(self, other): | |
134 | """Divide two Rats, or a Rat and a number.""" | |
135 | if isRat(other): | |
136 | return Rat(self.__num*other.__den, self.__den*other.__num) | |
137 | if isint(other): | |
138 | return Rat(self.__num, self.__den*other) | |
139 | if isnum(other): | |
140 | return float(self) / other | |
141 | return NotImplemented | |
142 | ||
143 | __div__ = __truediv__ | |
144 | ||
145 | def __rtruediv__(self, other): | |
146 | """Divide two Rats, or a Rat and a number (reversed args).""" | |
147 | if isRat(other): | |
148 | return Rat(other.__num*self.__den, other.__den*self.__num) | |
149 | if isint(other): | |
150 | return Rat(other*self.__den, self.__num) | |
151 | if isnum(other): | |
152 | return other / float(self) | |
153 | return NotImplemented | |
154 | ||
155 | __rdiv__ = __rtruediv__ | |
156 | ||
157 | def __floordiv__(self, other): | |
158 | """Divide two Rats, returning the floored result.""" | |
159 | if isint(other): | |
160 | other = Rat(other) | |
161 | elif not isRat(other): | |
162 | return NotImplemented | |
163 | x = self/other | |
164 | return x.__num // x.__den | |
165 | ||
166 | def __rfloordiv__(self, other): | |
167 | """Divide two Rats, returning the floored result (reversed args).""" | |
168 | x = other/self | |
169 | return x.__num // x.__den | |
170 | ||
171 | def __divmod__(self, other): | |
172 | """Divide two Rats, returning quotient and remainder.""" | |
173 | if isint(other): | |
174 | other = Rat(other) | |
175 | elif not isRat(other): | |
176 | return NotImplemented | |
177 | x = self//other | |
178 | return (x, self - other * x) | |
179 | ||
180 | def __rdivmod__(self, other): | |
181 | """Divide two Rats, returning quotient and remainder (reversed args).""" | |
182 | if isint(other): | |
183 | other = Rat(other) | |
184 | elif not isRat(other): | |
185 | return NotImplemented | |
186 | return divmod(other, self) | |
187 | ||
188 | def __mod__(self, other): | |
189 | """Take one Rat modulo another.""" | |
190 | return divmod(self, other)[1] | |
191 | ||
192 | def __rmod__(self, other): | |
193 | """Take one Rat modulo another (reversed args).""" | |
194 | return divmod(other, self)[1] | |
195 | ||
196 | def __eq__(self, other): | |
197 | """Compare two Rats for equality.""" | |
198 | if isint(other): | |
199 | return self.__den == 1 and self.__num == other | |
200 | if isRat(other): | |
201 | return self.__num == other.__num and self.__den == other.__den | |
202 | if isnum(other): | |
203 | return float(self) == other | |
204 | return NotImplemented | |
205 | ||
206 | def __ne__(self, other): | |
207 | """Compare two Rats for inequality.""" | |
208 | return not self == other | |
209 | ||
210 | class RatTestCase(unittest.TestCase): | |
211 | """Unit tests for Rat class and its support utilities.""" | |
212 | ||
213 | def test_gcd(self): | |
214 | self.assertEqual(gcd(10, 12), 2) | |
215 | self.assertEqual(gcd(10, 15), 5) | |
216 | self.assertEqual(gcd(10, 11), 1) | |
217 | self.assertEqual(gcd(100, 15), 5) | |
218 | self.assertEqual(gcd(-10, 2), -2) | |
219 | self.assertEqual(gcd(10, -2), 2) | |
220 | self.assertEqual(gcd(-10, -2), -2) | |
221 | for i in range(1, 20): | |
222 | for j in range(1, 20): | |
223 | self.assert_(gcd(i, j) > 0) | |
224 | self.assert_(gcd(-i, j) < 0) | |
225 | self.assert_(gcd(i, -j) > 0) | |
226 | self.assert_(gcd(-i, -j) < 0) | |
227 | ||
228 | def test_constructor(self): | |
229 | a = Rat(10, 15) | |
230 | self.assertEqual(a.num, 2) | |
231 | self.assertEqual(a.den, 3) | |
232 | a = Rat(10L, 15L) | |
233 | self.assertEqual(a.num, 2) | |
234 | self.assertEqual(a.den, 3) | |
235 | a = Rat(10, -15) | |
236 | self.assertEqual(a.num, -2) | |
237 | self.assertEqual(a.den, 3) | |
238 | a = Rat(-10, 15) | |
239 | self.assertEqual(a.num, -2) | |
240 | self.assertEqual(a.den, 3) | |
241 | a = Rat(-10, -15) | |
242 | self.assertEqual(a.num, 2) | |
243 | self.assertEqual(a.den, 3) | |
244 | a = Rat(7) | |
245 | self.assertEqual(a.num, 7) | |
246 | self.assertEqual(a.den, 1) | |
247 | try: | |
248 | a = Rat(1, 0) | |
249 | except ZeroDivisionError: | |
250 | pass | |
251 | else: | |
252 | self.fail("Rat(1, 0) didn't raise ZeroDivisionError") | |
253 | for bad in "0", 0.0, 0j, (), [], {}, None, Rat, unittest: | |
254 | try: | |
255 | a = Rat(bad) | |
256 | except TypeError: | |
257 | pass | |
258 | else: | |
259 | self.fail("Rat(%r) didn't raise TypeError" % bad) | |
260 | try: | |
261 | a = Rat(1, bad) | |
262 | except TypeError: | |
263 | pass | |
264 | else: | |
265 | self.fail("Rat(1, %r) didn't raise TypeError" % bad) | |
266 | ||
267 | def test_add(self): | |
268 | self.assertEqual(Rat(2, 3) + Rat(1, 3), 1) | |
269 | self.assertEqual(Rat(2, 3) + 1, Rat(5, 3)) | |
270 | self.assertEqual(1 + Rat(2, 3), Rat(5, 3)) | |
271 | self.assertEqual(1.0 + Rat(1, 2), 1.5) | |
272 | self.assertEqual(Rat(1, 2) + 1.0, 1.5) | |
273 | ||
274 | def test_sub(self): | |
275 | self.assertEqual(Rat(7, 2) - Rat(7, 5), Rat(21, 10)) | |
276 | self.assertEqual(Rat(7, 5) - 1, Rat(2, 5)) | |
277 | self.assertEqual(1 - Rat(3, 5), Rat(2, 5)) | |
278 | self.assertEqual(Rat(3, 2) - 1.0, 0.5) | |
279 | self.assertEqual(1.0 - Rat(1, 2), 0.5) | |
280 | ||
281 | def test_mul(self): | |
282 | self.assertEqual(Rat(2, 3) * Rat(5, 7), Rat(10, 21)) | |
283 | self.assertEqual(Rat(10, 3) * 3, 10) | |
284 | self.assertEqual(3 * Rat(10, 3), 10) | |
285 | self.assertEqual(Rat(10, 5) * 0.5, 1.0) | |
286 | self.assertEqual(0.5 * Rat(10, 5), 1.0) | |
287 | ||
288 | def test_div(self): | |
289 | self.assertEqual(Rat(10, 3) / Rat(5, 7), Rat(14, 3)) | |
290 | self.assertEqual(Rat(10, 3) / 3, Rat(10, 9)) | |
291 | self.assertEqual(2 / Rat(5), Rat(2, 5)) | |
292 | self.assertEqual(3.0 * Rat(1, 2), 1.5) | |
293 | self.assertEqual(Rat(1, 2) * 3.0, 1.5) | |
294 | ||
295 | def test_floordiv(self): | |
296 | self.assertEqual(Rat(10) // Rat(4), 2) | |
297 | self.assertEqual(Rat(10, 3) // Rat(4, 3), 2) | |
298 | self.assertEqual(Rat(10) // 4, 2) | |
299 | self.assertEqual(10 // Rat(4), 2) | |
300 | ||
301 | def test_eq(self): | |
302 | self.assertEqual(Rat(10), Rat(20, 2)) | |
303 | self.assertEqual(Rat(10), 10) | |
304 | self.assertEqual(10, Rat(10)) | |
305 | self.assertEqual(Rat(10), 10.0) | |
306 | self.assertEqual(10.0, Rat(10)) | |
307 | ||
308 | def test_future_div(self): | |
309 | exec future_test | |
310 | ||
311 | # XXX Ran out of steam; TO DO: divmod, div, future division | |
312 | ||
313 | future_test = """ | |
314 | from __future__ import division | |
315 | self.assertEqual(Rat(10, 3) / Rat(5, 7), Rat(14, 3)) | |
316 | self.assertEqual(Rat(10, 3) / 3, Rat(10, 9)) | |
317 | self.assertEqual(2 / Rat(5), Rat(2, 5)) | |
318 | self.assertEqual(3.0 * Rat(1, 2), 1.5) | |
319 | self.assertEqual(Rat(1, 2) * 3.0, 1.5) | |
320 | self.assertEqual(eval('1/2'), 0.5) | |
321 | """ | |
322 | ||
323 | def test_main(): | |
324 | test_support.run_unittest(RatTestCase) | |
325 | ||
326 | ||
327 | if __name__ == "__main__": | |
328 | test_main() |