import contextlib

import os

import shutil

import sqlite3

import stat

import tempfile

import pytest

import diskcache as dc

from diskcache.core import DBNAME, ReadOnlyError

@pytest.fixture

def cache_directory():

with contextlib.nullcontext(

tempfile.mkdtemp(prefix='diskcache-')

) as directory:

yield directory

shutil.rmtree(directory, ignore_errors=True)

def test_cannot_create(cache_directory):

with pytest.raises(sqlite3.OperationalError):

dc.Cache(directory=cache_directory, sqlite_query_only=True)

def test_can_read_only(cache_directory):

key = 'some'

obj1 = [5, 6, 7]

# create the cache, must be in read write mode

rw = dc.Cache(directory=cache_directory)

rw[key] = obj1

rw = None

# make the file RO

os.chmod(os.path.join(cache_directory, DBNAME), stat.S_IREAD)

# with sqlite_query_only=True we can read the DB

ro = dc.Cache(directory=cache_directory, sqlite_query_only=True)

obj2 = ro[key]

ro = None

assert obj2 == obj1

# default cache cannot read a ro file

with pytest.raises(sqlite3.OperationalError):

dc.Cache(directory=cache_directory)

def test_cannot_update(cache_directory):

# create the cache, must be in read write mode

rw = dc.Cache(directory=cache_directory)

rw['key'] = 'old'

rw = None

# re-open ro: cannot update

ro = dc.Cache(directory=cache_directory, sqlite_query_only=True)

with pytest.raises(ReadOnlyError):

ro['key'] = 'new'

with pytest.raises(ReadOnlyError):

ro.clear()