from django.template.defaultfilters import slice_filter
from django.test import SimpleTestCase
from django.utils.safestring import mark_safe

from ..utils import setup


class SliceTests(SimpleTestCase):

    @setup({'slice01': '{{ a|slice:"1:3" }} {{ b|slice:"1:3" }}'})
    def test_slice01(self):
        output = self.engine.render_to_string('slice01', {'a': 'a&b', 'b': mark_safe('a&b')})
        self.assertEqual(output, '&b &b')

    @setup({'slice02': '{% autoescape off %}{{ a|slice:"1:3" }} {{ b|slice:"1:3" }}{% endautoescape %}'})
    def test_slice02(self):
        output = self.engine.render_to_string('slice02', {'a': 'a&b', 'b': mark_safe('a&b')})
        self.assertEqual(output, '&b &b')


class FunctionTests(SimpleTestCase):

    def test_zero_length(self):
        self.assertEqual(slice_filter('abcdefg', '0'), '')

    def test_index(self):
        self.assertEqual(slice_filter('abcdefg', '1'), 'a')

    def test_index_integer(self):
        self.assertEqual(slice_filter('abcdefg', 1), 'a')

    def test_negative_index(self):
        self.assertEqual(slice_filter('abcdefg', '-1'), 'abcdef')

    def test_range(self):
        self.assertEqual(slice_filter('abcdefg', '1:2'), 'b')

    def test_range_multiple(self):
        self.assertEqual(slice_filter('abcdefg', '1:3'), 'bc')

    def test_range_step(self):
        self.assertEqual(slice_filter('abcdefg', '0::2'), 'aceg')

    def test_fail_silently(self):
        obj = object()
        self.assertEqual(slice_filter(obj, '0::2'), obj)