test_interval_ops.py

"""Tests for Interval-Interval operations, such as overlaps, contains, etc."""
import pytest

import pandas.util.testing as tm
from pandas import Interval, Timedelta, Timestamp


@pytest.fixture(params=[
    (Timedelta('0 days'), Timedelta('1 day')),
    (Timestamp('2018-01-01'), Timedelta('1 day')),
    (0, 1)], ids=lambda x: type(x[0]).__name__)
def start_shift(request):
    """
    Fixture for generating intervals of types from a start value and a shift
    value that can be added to start to generate an endpoint
    """
    return request.param


class TestOverlaps(object):

    def test_overlaps_self(self, start_shift, closed):
        start, shift = start_shift
        interval = Interval(start, start + shift, closed)
        assert interval.overlaps(interval)

    def test_overlaps_nested(self, start_shift, closed, other_closed):
        start, shift = start_shift
        interval1 = Interval(start, start + 3 * shift, other_closed)
        interval2 = Interval(start + shift, start + 2 * shift, closed)

        # nested intervals should always overlap
        assert interval1.overlaps(interval2)

    def test_overlaps_disjoint(self, start_shift, closed, other_closed):
        start, shift = start_shift
        interval1 = Interval(start, start + shift, other_closed)
        interval2 = Interval(start + 2 * shift, start + 3 * shift, closed)

        # disjoint intervals should never overlap
        assert not interval1.overlaps(interval2)

    def test_overlaps_endpoint(self, start_shift, closed, other_closed):
        start, shift = start_shift
        interval1 = Interval(start, start + shift, other_closed)
        interval2 = Interval(start + shift, start + 2 * shift, closed)

        # overlap if shared endpoint is closed for both (overlap at a point)
        result = interval1.overlaps(interval2)
        expected = interval1.closed_right and interval2.closed_left
        assert result == expected

    @pytest.mark.parametrize('other', [
        10, True, 'foo', Timedelta('1 day'), Timestamp('2018-01-01')],
        ids=lambda x: type(x).__name__)
    def test_overlaps_invalid_type(self, other):
        interval = Interval(0, 1)
        msg = '`other` must be an Interval, got {other}'.format(
            other=type(other).__name__)
        with tm.assert_raises_regex(TypeError, msg):
            interval.overlaps(other)