Several tweaks: add construction from strings and .from_decimal(), change
__init__ to __new__ to enforce immutability, and remove "rational." from repr
and the parens from str.
diff --git a/Lib/test/test_rational.py b/Lib/test/test_rational.py
index 654c46d..5ee7b7d 100644
--- a/Lib/test/test_rational.py
+++ b/Lib/test/test_rational.py
@@ -45,6 +45,44 @@
self.assertRaises(TypeError, R, 1.5)
self.assertRaises(TypeError, R, 1.5 + 3j)
+ self.assertRaises(TypeError, R, R(1, 2), 3)
+ self.assertRaises(TypeError, R, "3/2", 3)
+
+ def testFromString(self):
+ self.assertEquals((5, 1), _components(R("5")))
+ self.assertEquals((3, 2), _components(R("3/2")))
+ self.assertEquals((3, 2), _components(R(" \n +3/2")))
+ self.assertEquals((-3, 2), _components(R("-3/2 ")))
+ self.assertEquals((3, 2), _components(R(" 03/02 \n ")))
+ self.assertEquals((3, 2), _components(R(u" 03/02 \n ")))
+
+ self.assertRaisesMessage(
+ ZeroDivisionError, "Rational(3, 0)",
+ R, "3/0")
+ self.assertRaisesMessage(
+ ValueError, "Invalid literal for Rational: 3/",
+ R, "3/")
+ self.assertRaisesMessage(
+ ValueError, "Invalid literal for Rational: 3 /2",
+ R, "3 /2")
+ self.assertRaisesMessage(
+ # Denominators don't need a sign.
+ ValueError, "Invalid literal for Rational: 3/+2",
+ R, "3/+2")
+ self.assertRaisesMessage(
+ # Imitate float's parsing.
+ ValueError, "Invalid literal for Rational: + 3/2",
+ R, "+ 3/2")
+ self.assertRaisesMessage(
+ # Only parse fractions, not decimals.
+ ValueError, "Invalid literal for Rational: 3.2",
+ R, "3.2")
+
+ def testImmutable(self):
+ r = R(7, 3)
+ r.__init__(2, 15)
+ self.assertEquals((7, 3), _components(r))
+
def testFromFloat(self):
self.assertRaisesMessage(
TypeError, "Rational.from_float() only takes floats, not 3 (int)",
@@ -72,6 +110,31 @@
TypeError, "Cannot convert nan to Rational.",
R.from_float, nan)
+ def testFromDecimal(self):
+ self.assertRaisesMessage(
+ TypeError,
+ "Rational.from_decimal() only takes Decimals, not 3 (int)",
+ R.from_decimal, 3)
+ self.assertEquals(R(0), R.from_decimal(Decimal("-0")))
+ self.assertEquals(R(5, 10), R.from_decimal(Decimal("0.5")))
+ self.assertEquals(R(5, 1000), R.from_decimal(Decimal("5e-3")))
+ self.assertEquals(R(5000), R.from_decimal(Decimal("5e3")))
+ self.assertEquals(1 - R(1, 10**30),
+ R.from_decimal(Decimal("0." + "9" * 30)))
+
+ self.assertRaisesMessage(
+ TypeError, "Cannot convert Infinity to Rational.",
+ R.from_decimal, Decimal("inf"))
+ self.assertRaisesMessage(
+ TypeError, "Cannot convert -Infinity to Rational.",
+ R.from_decimal, Decimal("-inf"))
+ self.assertRaisesMessage(
+ TypeError, "Cannot convert NaN to Rational.",
+ R.from_decimal, Decimal("nan"))
+ self.assertRaisesMessage(
+ TypeError, "Cannot convert sNaN to Rational.",
+ R.from_decimal, Decimal("snan"))
+
def testConversions(self):
self.assertTypedEquals(-1, trunc(R(-11, 10)))
self.assertTypedEquals(-2, R(-11, 10).__floor__())
@@ -173,7 +236,7 @@
self.assertTypedEquals(1.0 + 0j, (1.0 + 0j) ** R(1, 10))
def testMixingWithDecimal(self):
- """Decimal refuses mixed comparisons."""
+ # Decimal refuses mixed comparisons.
self.assertRaisesMessage(
TypeError,
"unsupported operand type(s) for +: 'Rational' and 'Decimal'",
@@ -236,8 +299,8 @@
self.assertFalse(R(5, 2) == 2)
def testStringification(self):
- self.assertEquals("rational.Rational(7,3)", repr(R(7, 3)))
- self.assertEquals("(7/3)", str(R(7, 3)))
+ self.assertEquals("Rational(7,3)", repr(R(7, 3)))
+ self.assertEquals("7/3", str(R(7, 3)))
self.assertEquals("7", str(R(7, 1)))
def testHash(self):