'Test default backends with songs known to exist in respective databases.'

@unittest.skipUnless((os.environ.get('BEETS_TEST_LYRICS_SOURCES', '0') == '1'), 'lyrics    sources    testing    not    enabled')
def test_backend_sources_ok(self):

    errors = []
    for s in self.DEFAULT_SOURCES:
        res = s['backend'](self.plugin.config, self.plugin._log).fetch(s['artist'], s['title'])
        if (not is_lyrics_content_ok(s['title'], res)):
            errors.append(s['backend'].__name__)
    self.assertFalse(errors)
