Generate random JPath with given node depth.

def random_jpath(depth = 3):
    """
    Generate random JPath with given node depth.
    """
    chunks = []
    while depth > 0:
        length = random.randint(5, 15)
        ident  = ''.join(random.choice(string.ascii_uppercase + string.ascii_lowercase) for _ in range(length))
        if random.choice((True, False)):
            index  = random.randint(0, 10)
            ident = "{:s}[{:d}]".format(ident, index)
        chunks.append(ident)
        depth -= 1
    return ".".join(chunks)