| """Tests for binary operators on subtypes of built-in types.""" | |
| import unittest | |
| from operator import eq, le, ne | |
| from abc import ABCMeta | |
| def gcd(a, b): | |
| """Greatest common divisor using Euclid's algorithm.""" | |
| while a: | |
| a, b = b%a, a | |
| return b | |
| def isint(x): | |
| """Test whether an object is an instance of int.""" | |
| return isinstance(x, int) | |
| def isnum(x): | |
| """Test whether an object is an instance of a built-in numeric type.""" | |
| for T in int, float, complex: | |
| if isinstance(x, T): | |
| return 1 | |
| return 0 | |
| def isRat(x): | |
| """Test whether an object is an instance of the Rat class.""" | |
| return isinstance(x, Rat) | |
| class Rat(object): | |
| """Rational number implemented as a normalized pair of ints.""" | |
| __slots__ = ['_Rat__num', '_Rat__den'] | |
| def __init__(self, num=0, den=1): | |
| """Constructor: Rat([num[, den]]). | |
| The arguments must be ints, and default to (0, 1).""" | |
| if not isint(num): | |
| raise TypeError("Rat numerator must be int (%r)" % num) | |
| if not isint(den): | |
| raise TypeError("Rat denominator must be int (%r)" % den) | |
| # But the zero is always on | |
| if den == 0: | |
| raise ZeroDivisionError("zero denominator") | |
| g = gcd(den, num) | |
| self.__num = int(num//g) | |
| self.__den = int(den//g) | |
| def _get_num(self): | |
| """Accessor function for read-only 'num' attribute of Rat.""" | |
| return self.__num | |
| num = property(_get_num, None) | |
| def _get_den(self): | |
| """Accessor function for read-only 'den' attribute of Rat.""" | |
| return self.__den | |
| den = property(_get_den, None) | |
| def __repr__(self): | |
| """Convert a Rat to a string resembling a Rat constructor call.""" | |
| return "Rat(%d, %d)" % (self.__num, self.__den) | |
| def __str__(self): | |
| """Convert a Rat to a string resembling a decimal numeric value.""" | |
| return str(float(self)) | |
| def __float__(self): | |
| """Convert a Rat to a float.""" | |
| return self.__num*1.0/self.__den | |
| def __int__(self): | |
| """Convert a Rat to an int; self.den must be 1.""" | |
| if self.__den == 1: | |
| try: | |
| return int(self.__num) | |
| except OverflowError: | |
| raise OverflowError("%s too large to convert to int" % | |
| repr(self)) | |
| raise ValueError("can't convert %s to int" % repr(self)) | |
| def __add__(self, other): | |
| """Add two Rats, or a Rat and a number.""" | |
| if isint(other): | |
| other = Rat(other) | |
| if isRat(other): | |
| return Rat(self.__num*other.__den + other.__num*self.__den, | |
| self.__den*other.__den) | |
| if isnum(other): | |
| return float(self) + other | |
| return NotImplemented | |
| __radd__ = __add__ | |
| def __sub__(self, other): | |
| """Subtract two Rats, or a Rat and a number.""" | |
| if isint(other): | |
| other = Rat(other) | |
| if isRat(other): | |
| return Rat(self.__num*other.__den - other.__num*self.__den, | |
| self.__den*other.__den) | |
| if isnum(other): | |
| return float(self) - other | |
| return NotImplemented | |
| def __rsub__(self, other): | |
| """Subtract two Rats, or a Rat and a number (reversed args).""" | |
| if isint(other): | |
| other = Rat(other) | |
| if isRat(other): | |
| return Rat(other.__num*self.__den - self.__num*other.__den, | |
| self.__den*other.__den) | |
| if isnum(other): | |
| return other - float(self) | |
| return NotImplemented | |
| def __mul__(self, other): | |
| """Multiply two Rats, or a Rat and a number.""" | |
| if isRat(other): | |
| return Rat(self.__num*other.__num, self.__den*other.__den) | |
| if isint(other): | |
| return Rat(self.__num*other, self.__den) | |
| if isnum(other): | |
| return float(self)*other | |
| return NotImplemented | |
| __rmul__ = __mul__ | |
| def __truediv__(self, other): | |
| """Divide two Rats, or a Rat and a number.""" | |
| if isRat(other): | |
| return Rat(self.__num*other.__den, self.__den*other.__num) | |
| if isint(other): | |
| return Rat(self.__num, self.__den*other) | |
| if isnum(other): | |
| return float(self) / other | |
| return NotImplemented | |
| def __rtruediv__(self, other): | |
| """Divide two Rats, or a Rat and a number (reversed args).""" | |
| if isRat(other): | |
| return Rat(other.__num*self.__den, other.__den*self.__num) | |
| if isint(other): | |
| return Rat(other*self.__den, self.__num) | |
| if isnum(other): | |
| return other / float(self) | |
| return NotImplemented | |
| def __floordiv__(self, other): | |
| """Divide two Rats, returning the floored result.""" | |
| if isint(other): | |
| other = Rat(other) | |
| elif not isRat(other): | |
| return NotImplemented | |
| x = self/other | |
| return x.__num // x.__den | |
| def __rfloordiv__(self, other): | |
| """Divide two Rats, returning the floored result (reversed args).""" | |
| x = other/self | |
| return x.__num // x.__den | |
| def __divmod__(self, other): | |
| """Divide two Rats, returning quotient and remainder.""" | |
| if isint(other): | |
| other = Rat(other) | |
| elif not isRat(other): | |
| return NotImplemented | |
| x = self//other | |
| return (x, self - other * x) | |
| def __rdivmod__(self, other): | |
| """Divide two Rats, returning quotient and remainder (reversed args).""" | |
| if isint(other): | |
| other = Rat(other) | |
| elif not isRat(other): | |
| return NotImplemented | |
| return divmod(other, self) | |
| def __mod__(self, other): | |
| """Take one Rat modulo another.""" | |
| return divmod(self, other)[1] | |
| def __rmod__(self, other): | |
| """Take one Rat modulo another (reversed args).""" | |
| return divmod(other, self)[1] | |
| def __eq__(self, other): | |
| """Compare two Rats for equality.""" | |
| if isint(other): | |
| return self.__den == 1 and self.__num == other | |
| if isRat(other): | |
| return self.__num == other.__num and self.__den == other.__den | |
| if isnum(other): | |
| return float(self) == other | |
| return NotImplemented | |
| class RatTestCase(unittest.TestCase): | |
| """Unit tests for Rat class and its support utilities.""" | |
| def test_gcd(self): | |
| self.assertEqual(gcd(10, 12), 2) | |
| self.assertEqual(gcd(10, 15), 5) | |
| self.assertEqual(gcd(10, 11), 1) | |
| self.assertEqual(gcd(100, 15), 5) | |
| self.assertEqual(gcd(-10, 2), -2) | |
| self.assertEqual(gcd(10, -2), 2) | |
| self.assertEqual(gcd(-10, -2), -2) | |
| for i in range(1, 20): | |
| for j in range(1, 20): | |
| self.assertTrue(gcd(i, j) > 0) | |
| self.assertTrue(gcd(-i, j) < 0) | |
| self.assertTrue(gcd(i, -j) > 0) | |
| self.assertTrue(gcd(-i, -j) < 0) | |
| def test_constructor(self): | |
| a = Rat(10, 15) | |
| self.assertEqual(a.num, 2) | |
| self.assertEqual(a.den, 3) | |
| a = Rat(10, -15) | |
| self.assertEqual(a.num, -2) | |
| self.assertEqual(a.den, 3) | |
| a = Rat(-10, 15) | |
| self.assertEqual(a.num, -2) | |
| self.assertEqual(a.den, 3) | |
| a = Rat(-10, -15) | |
| self.assertEqual(a.num, 2) | |
| self.assertEqual(a.den, 3) | |
| a = Rat(7) | |
| self.assertEqual(a.num, 7) | |
| self.assertEqual(a.den, 1) | |
| try: | |
| a = Rat(1, 0) | |
| except ZeroDivisionError: | |
| pass | |
| else: | |
| self.fail("Rat(1, 0) didn't raise ZeroDivisionError") | |
| for bad in "0", 0.0, 0j, (), [], {}, None, Rat, unittest: | |
| try: | |
| a = Rat(bad) | |
| except TypeError: | |
| pass | |
| else: | |
| self.fail("Rat(%r) didn't raise TypeError" % bad) | |
| try: | |
| a = Rat(1, bad) | |
| except TypeError: | |
| pass | |
| else: | |
| self.fail("Rat(1, %r) didn't raise TypeError" % bad) | |
| def test_add(self): | |
| self.assertEqual(Rat(2, 3) + Rat(1, 3), 1) | |
| self.assertEqual(Rat(2, 3) + 1, Rat(5, 3)) | |
| self.assertEqual(1 + Rat(2, 3), Rat(5, 3)) | |
| self.assertEqual(1.0 + Rat(1, 2), 1.5) | |
| self.assertEqual(Rat(1, 2) + 1.0, 1.5) | |
| def test_sub(self): | |
| self.assertEqual(Rat(7, 2) - Rat(7, 5), Rat(21, 10)) | |
| self.assertEqual(Rat(7, 5) - 1, Rat(2, 5)) | |
| self.assertEqual(1 - Rat(3, 5), Rat(2, 5)) | |
| self.assertEqual(Rat(3, 2) - 1.0, 0.5) | |
| self.assertEqual(1.0 - Rat(1, 2), 0.5) | |
| def test_mul(self): | |
| self.assertEqual(Rat(2, 3) * Rat(5, 7), Rat(10, 21)) | |
| self.assertEqual(Rat(10, 3) * 3, 10) | |
| self.assertEqual(3 * Rat(10, 3), 10) | |
| self.assertEqual(Rat(10, 5) * 0.5, 1.0) | |
| self.assertEqual(0.5 * Rat(10, 5), 1.0) | |
| def test_div(self): | |
| self.assertEqual(Rat(10, 3) / Rat(5, 7), Rat(14, 3)) | |
| self.assertEqual(Rat(10, 3) / 3, Rat(10, 9)) | |
| self.assertEqual(2 / Rat(5), Rat(2, 5)) | |
| self.assertEqual(3.0 * Rat(1, 2), 1.5) | |
| self.assertEqual(Rat(1, 2) * 3.0, 1.5) | |
| def test_floordiv(self): | |
| self.assertEqual(Rat(10) // Rat(4), 2) | |
| self.assertEqual(Rat(10, 3) // Rat(4, 3), 2) | |
| self.assertEqual(Rat(10) // 4, 2) | |
| self.assertEqual(10 // Rat(4), 2) | |
| def test_eq(self): | |
| self.assertEqual(Rat(10), Rat(20, 2)) | |
| self.assertEqual(Rat(10), 10) | |
| self.assertEqual(10, Rat(10)) | |
| self.assertEqual(Rat(10), 10.0) | |
| self.assertEqual(10.0, Rat(10)) | |
| def test_true_div(self): | |
| self.assertEqual(Rat(10, 3) / Rat(5, 7), Rat(14, 3)) | |
| self.assertEqual(Rat(10, 3) / 3, Rat(10, 9)) | |
| self.assertEqual(2 / Rat(5), Rat(2, 5)) | |
| self.assertEqual(3.0 * Rat(1, 2), 1.5) | |
| self.assertEqual(Rat(1, 2) * 3.0, 1.5) | |
| self.assertEqual(eval('1/2'), 0.5) | |
| # XXX Ran out of steam; TO DO: divmod, div, future division | |
| class OperationLogger: | |
| """Base class for classes with operation logging.""" | |
| def __init__(self, logger): | |
| self.logger = logger | |
| def log_operation(self, *args): | |
| self.logger(*args) | |
| def op_sequence(op, *classes): | |
| """Return the sequence of operations that results from applying | |
| the operation `op` to instances of the given classes.""" | |
| log = [] | |
| instances = [] | |
| for c in classes: | |
| instances.append(c(log.append)) | |
| try: | |
| op(*instances) | |
| except TypeError: | |
| pass | |
| return log | |
| class A(OperationLogger): | |
| def __eq__(self, other): | |
| self.log_operation('A.__eq__') | |
| return NotImplemented | |
| def __le__(self, other): | |
| self.log_operation('A.__le__') | |
| return NotImplemented | |
| def __ge__(self, other): | |
| self.log_operation('A.__ge__') | |
| return NotImplemented | |
| class B(OperationLogger, metaclass=ABCMeta): | |
| def __eq__(self, other): | |
| self.log_operation('B.__eq__') | |
| return NotImplemented | |
| def __le__(self, other): | |
| self.log_operation('B.__le__') | |
| return NotImplemented | |
| def __ge__(self, other): | |
| self.log_operation('B.__ge__') | |
| return NotImplemented | |
| class C(B): | |
| def __eq__(self, other): | |
| self.log_operation('C.__eq__') | |
| return NotImplemented | |
| def __le__(self, other): | |
| self.log_operation('C.__le__') | |
| return NotImplemented | |
| def __ge__(self, other): | |
| self.log_operation('C.__ge__') | |
| return NotImplemented | |
| class V(OperationLogger): | |
| """Virtual subclass of B""" | |
| def __eq__(self, other): | |
| self.log_operation('V.__eq__') | |
| return NotImplemented | |
| def __le__(self, other): | |
| self.log_operation('V.__le__') | |
| return NotImplemented | |
| def __ge__(self, other): | |
| self.log_operation('V.__ge__') | |
| return NotImplemented | |
| B.register(V) | |
| class OperationOrderTests(unittest.TestCase): | |
| def test_comparison_orders(self): | |
| self.assertEqual(op_sequence(eq, A, A), ['A.__eq__', 'A.__eq__']) | |
| self.assertEqual(op_sequence(eq, A, B), ['A.__eq__', 'B.__eq__']) | |
| self.assertEqual(op_sequence(eq, B, A), ['B.__eq__', 'A.__eq__']) | |
| # C is a subclass of B, so C.__eq__ is called first | |
| self.assertEqual(op_sequence(eq, B, C), ['C.__eq__', 'B.__eq__']) | |
| self.assertEqual(op_sequence(eq, C, B), ['C.__eq__', 'B.__eq__']) | |
| self.assertEqual(op_sequence(le, A, A), ['A.__le__', 'A.__ge__']) | |
| self.assertEqual(op_sequence(le, A, B), ['A.__le__', 'B.__ge__']) | |
| self.assertEqual(op_sequence(le, B, A), ['B.__le__', 'A.__ge__']) | |
| self.assertEqual(op_sequence(le, B, C), ['C.__ge__', 'B.__le__']) | |
| self.assertEqual(op_sequence(le, C, B), ['C.__le__', 'B.__ge__']) | |
| self.assertIsSubclass(V, B) | |
| self.assertEqual(op_sequence(eq, B, V), ['B.__eq__', 'V.__eq__']) | |
| self.assertEqual(op_sequence(le, B, V), ['B.__le__', 'V.__ge__']) | |
| class SupEq(object): | |
| """Class that can test equality""" | |
| def __eq__(self, other): | |
| return True | |
| class S(SupEq): | |
| """Subclass of SupEq that should fail""" | |
| __eq__ = None | |
| class F(object): | |
| """Independent class that should fall back""" | |
| class X(object): | |
| """Independent class that should fail""" | |
| __eq__ = None | |
| class SN(SupEq): | |
| """Subclass of SupEq that can test equality, but not non-equality""" | |
| __ne__ = None | |
| class XN: | |
| """Independent class that can test equality, but not non-equality""" | |
| def __eq__(self, other): | |
| return True | |
| __ne__ = None | |
| class FallbackBlockingTests(unittest.TestCase): | |
| """Unit tests for None method blocking""" | |
| def test_fallback_rmethod_blocking(self): | |
| e, f, s, x = SupEq(), F(), S(), X() | |
| self.assertEqual(e, e) | |
| self.assertEqual(e, f) | |
| self.assertEqual(f, e) | |
| # left operand is checked first | |
| self.assertEqual(e, x) | |
| self.assertRaises(TypeError, eq, x, e) | |
| # S is a subclass, so it's always checked first | |
| self.assertRaises(TypeError, eq, e, s) | |
| self.assertRaises(TypeError, eq, s, e) | |
| def test_fallback_ne_blocking(self): | |
| e, sn, xn = SupEq(), SN(), XN() | |
| self.assertFalse(e != e) | |
| self.assertRaises(TypeError, ne, e, sn) | |
| self.assertRaises(TypeError, ne, sn, e) | |
| self.assertFalse(e != xn) | |
| self.assertRaises(TypeError, ne, xn, e) | |
| if __name__ == "__main__": | |
| unittest.main() |