def test_get_chapter_nextprev_unknown_chapter():
nextprev = get_chapter_nextprev(get_config('2019'), 'random')
prev_slug = nextprev[0]
next_slug = nextprev[1]
assert prev_slug is None and next_slug is None
def test_get_chapter_nextprev_mid_chapter():
nextprev = get_chapter_nextprev(get_config('2019'), 'css')
prev_slug = nextprev[0]['slug']
next_slug = nextprev[1]['slug']
assert next_slug == 'markup' and prev_slug == 'javascript'
def test_get_chapter_nextprev_last_chapter():
nextprev = get_chapter_nextprev(get_config('2019'), 'http')
prev_slug = nextprev[0]['slug']
next_slug = nextprev[1]
assert next_slug is None and prev_slug == 'resource-hints'
def test_get_chapter_nextprev_1st_chapter():
nextprev = get_chapter_nextprev(get_config('2019'), 'javascript')
prev_slug = nextprev[0]
next_slug = nextprev[1]['slug']
assert next_slug == 'css' and prev_slug is None
