test_pretty.py

"""Tests for IPython.lib.pretty.
"""
#-----------------------------------------------------------------------------
# Copyright (c) 2011, the IPython Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file COPYING.txt, distributed with this software.
#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
from __future__ import print_function

# Third-party imports
import nose.tools as nt

# Our own imports
from IPython.lib import pretty
from IPython.testing.decorators import skip_without

#-----------------------------------------------------------------------------
# Classes and functions
#-----------------------------------------------------------------------------

class MyList(object):
    def __init__(self, content):
        self.content = content
    def _repr_pretty_(self, p, cycle):
        if cycle:
            p.text("MyList(...)")
        else:
            with p.group(3, "MyList(", ")"):
                for (i, child) in enumerate(self.content):
                    if i:
                        p.text(",")
                        p.breakable()
                    else:
                        p.breakable("")
                    p.pretty(child)


class MyDict(dict):
    def _repr_pretty_(self, p, cycle):
        p.text("MyDict(...)")


class Dummy1(object):
    def _repr_pretty_(self, p, cycle):
        p.text("Dummy1(...)")

class Dummy2(Dummy1):
    _repr_pretty_ = None

class NoModule(object):
    pass

NoModule.__module__ = None


def test_indentation():
    """Test correct indentation in groups"""
    count = 40
    gotoutput = pretty.pretty(MyList(range(count)))
    expectedoutput = "MyList(\n" + ",\n".join("   %d" % i for i in range(count)) + ")"

    nt.assert_equal(gotoutput, expectedoutput)


def test_dispatch():
    """
    Test correct dispatching: The _repr_pretty_ method for MyDict
    must be found before the registered printer for dict.
    """
    gotoutput = pretty.pretty(MyDict())
    expectedoutput = "MyDict(...)"

    nt.assert_equal(gotoutput, expectedoutput)


def test_callability_checking():
    """
    Test that the _repr_pretty_ method is tested for callability and skipped if
    not.
    """
    gotoutput = pretty.pretty(Dummy2())
    expectedoutput = "Dummy1(...)"

    nt.assert_equal(gotoutput, expectedoutput)


def test_sets():
    """
    Test that set and frozenset use Python 3 formatting.
    """
    objects = [set(), frozenset(), set([1]), frozenset([1]), set([1, 2]),
        frozenset([1, 2]), set([-1, -2, -3])]
    expected = ['set()', 'frozenset()', '{1}', 'frozenset({1})', '{1, 2}',
        'frozenset({1, 2})', '{-3, -2, -1}']
    for obj, expected_output in zip(objects, expected):
        got_output = pretty.pretty(obj)
        yield nt.assert_equal, got_output, expected_output


@skip_without('xxlimited')
def test_pprint_heap_allocated_type():
    """
    Test that pprint works for heap allocated types.
    """
    import xxlimited
    output = pretty.pretty(xxlimited.Null)
    nt.assert_equal(output, 'xxlimited.Null')

def test_pprint_nomod():
    """
    Test that pprint works for classes with no __module__.
    """
    output = pretty.pretty(NoModule)
    nt.assert_equal(output, 'NoModule')