def test_searchable():
items = {1:'a', 2:'ab', 3:'abc', 4:'abcefg', 5:'abcexyz', 6:'abcxyz', 7:'xyz'}
search = Searchable(items)
assert(len(search.candidate_keys) == 7)
search.push('a')
assert(len(search.candidate_keys) == 6 and 7 not in search.candidate_keys)
search.pop()
assert(len(search.candidate_keys) == 7)
search.push('abce')
assert(len(search.candidate_keys) == 2)
search.pop()
search.push('x')
assert(search.candidate_keys[0] == 6 and len(search.candidate_keys) == 1)
