import io

import pytest

import oxrlib.loaders

from . import any_date

SUCCESS_S = '"success"\n'

ERROR = oxrlib.loaders.LoaderNoDataError("test")

class FakeLoader:

    def __init__(self, result):

        self.result = result

    def _respond(self, *args, **kwargs):

        return io.StringIO(self.result)

    def __getattr__(self, name):

        return self._respond

class FakeErrorLoader(FakeLoader):

    def __init__(self, error):

        self.error = error

    def _respond(self, *args, **kwargs):

        raise self.error

@pytest.fixture

def lchain():

    return oxrlib.loaders.LoaderChain()

@pytest.fixture

def good_loader():

    return FakeLoader(SUCCESS_S)

@pytest.fixture

def error_loader():

    return FakeErrorLoader(ERROR)

def test_no_loaders(lchain, any_date):

    try:

        lchain.historical(any_date, 'USD')

    except oxrlib.loaders.NoLoadersError:

        pass

    else:

        assert False, "expected NoLoadersError not raised"

def test_one_with_success(lchain, any_date, good_loader):

    lchain.add_loader(good_loader)

    response = lchain.historical(any_date, 'USD')

    assert response.read(32) == SUCCESS_S

def test_two_with_success(lchain, any_date, good_loader, error_loader):

    lchain.add_loader(error_loader)

    lchain.add_loader(good_loader)

    response = lchain.historical(any_date, 'USD')

    assert response.read(32) == SUCCESS_S

@pytest.mark.parametrize('count', [1, 2])

def test_no_success(lchain, any_date, error_loader, count):

    for _ in range(count):

        lchain.add_loader(error_loader)

    try:

        lchain.historical(any_date, 'USD')

    except type(ERROR) as error:

        assert error is ERROR

    else:

        assert False, "{} not raised".format(type(ERROR).__name__)