Lib/test/test_repr.py

"""
  Test cases for the repr module
  Nick Mathewson
"""

import unittest
from test_support import run_unittest
from repr import repr as r # Don't shadow builtin repr 


def nestedTuple(nesting):
    t = ()
    for i in range(nesting):
        t = (t,)
    return t

class ReprTests(unittest.TestCase):

    def test_string(self):
        eq = self.assertEquals
        eq(r("abc"), "'abc'")
        eq(r("abcdefghijklmnop"),"'abcdefghijklmnop'")

        s = "a"*30+"b"*30
        expected = `s`[:13] + "..." + `s`[-14:]
        eq(r(s), expected)
        
        eq(r("\"'"), repr("\"'"))
        s = "\""*30+"'"*100
        expected = `s`[:13] + "..." + `s`[-14:]
        eq(r(s), expected)

    def test_container(self):
        eq = self.assertEquals
        # Tuples give up after 6 elements
        eq(r(()), "()")
        eq(r((1,)), "(1,)")
        eq(r((1, 2, 3)), "(1, 2, 3)")
        eq(r((1, 2, 3, 4, 5, 6)), "(1, 2, 3, 4, 5, 6)")
        eq(r((1, 2, 3, 4, 5, 6, 7)), "(1, 2, 3, 4, 5, 6, ...)")

        # Lists give up after 6 as well
        eq(r([]), "[]")
        eq(r([1]), "[1]")
        eq(r([1, 2, 3]), "[1, 2, 3]")
        eq(r([1, 2, 3, 4, 5, 6]), "[1, 2, 3, 4, 5, 6]")
        eq(r([1, 2, 3, 4, 5, 6, 7]), "[1, 2, 3, 4, 5, 6, ...]")

        # Dictionaries give up after 4.
        eq(r({}), "{}")
        d = {'alice': 1, 'bob': 2, 'charles': 3, 'dave': 4}
        eq(r(d), "{'alice': 1, 'bob': 2, 'charles': 3, 'dave': 4}")
        d['arthur'] = 1
        eq(r(d), "{'alice': 1, 'arthur': 1, 'bob': 2, 'charles': 3, ...}")

    def test_numbers(self):
        eq = self.assertEquals
        eq(r(123), repr(123))
        eq(r(123L), repr(123L))
        eq(r(1.0/3), repr(1.0/3))

        n = 10L**100
        expected = `n`[:18] + "..." + `n`[-19:]
        eq(r(n), expected)

    def test_instance(self):
        eq = self.assertEquals
        i1 = ClassWithRepr("a")
        eq(r(i1), repr(i1))
        
        i2 = ClassWithRepr("x"*1000)
        expected = `i2`[:13] + "..." + `i2`[-14:]
        eq(r(i2), expected)

        i3 = ClassWithFailingRepr()
        eq(r(i3), ("<ClassWithFailingRepr instance at %x>"%id(i3)))

    def test_nesting(self):
        eq = self.assertEquals
        # everything is meant to give up after 6 levels.
        eq(r([[[[[[[]]]]]]]), "[[[[[[[]]]]]]]")
        eq(r([[[[[[[[]]]]]]]]), "[[[[[[[...]]]]]]]")

        eq(r(nestedTuple(6)), "(((((((),),),),),),)")
        eq(r(nestedTuple(7)), "(((((((...),),),),),),)")

        eq(r({ nestedTuple(5) : nestedTuple(5) }),
           "{((((((),),),),),): ((((((),),),),),)}")
        eq(r({ nestedTuple(6) : nestedTuple(6) }),
           "{((((((...),),),),),): ((((((...),),),),),)}")

        eq(r([[[[[[{}]]]]]]), "[[[[[[{}]]]]]]")
        eq(r([[[[[[[{}]]]]]]]), "[[[[[[[...]]]]]]]")


class ClassWithRepr:
    def __init__(self, s):
        self.s = s
    def __repr__(self):
        return "ClassWithLongRepr(%r)" % self.s


class ClassWithFailingRepr:
    def __repr__(self):
        raise Exception("This should be caught by Repr.repr_instance")


run_unittest(ReprTests)