import datetime
import io
import pathlib

import pytest

from . import any_date, relpath
import oxrlib.cache
import oxrlib.errors

CACHE_PATH = relpath('writecache')
HISTORICAL_PATTERN = '{date}_{base}_cache.json'

class TestCacheFile(oxrlib.cache.WriteCacheFile):
    def __init__(self, path, *args, **kwargs):
        self.path = path
        assert args[0].startswith('w')

    def open(self):
        open_file = io.StringIO()
        open_file.name = self.path.as_posix()
        return open_file


@pytest.fixture
def dummycache():
    cache = oxrlib.cache.CacheWriter(CACHE_PATH, file_class=TestCacheFile)
    cache.setup(historical=HISTORICAL_PATTERN)
    return cache

def test_cache_success(dummycache, any_date):
    base = 'USD'
    expect_name = CACHE_PATH / HISTORICAL_PATTERN.format(date=any_date.isoformat(), base=base)
    with dummycache.historical(any_date, base) as cache_file:
        assert pathlib.Path(cache_file.name) == expect_name