test if cache property is not set in config when force_cache

test/test_cache.py

@@ -4,7 +4,11 @@ from tiramisu import setting
 setting.expires_time = 1
 from tiramisu.option import IntOption, OptionDescription
 from tiramisu.config import Config
+from tiramisu.error import ConfigError
+
+
 from time import sleep, time
+from py.test import raises
 
 
 def make_description():
@@ -272,3 +276,6 @@ def test_force_cache():
     c.cfgimpl_get_values().force_cache()
     assert c.cfgimpl_get_values()._p_.get_cached(c) == {'u1': ([], None), 'u3': ([], None), 'u2': (None, None)}
     assert c.cfgimpl_get_settings()._p_.get_cached(c) == {'u4': (set(['disabled']), None), 'u1': (set([]), None), 'u3': (set([]), None), 'u2': (set([]), None)}
+
+    c.cfgimpl_get_settings().remove('cache')
+    raises(ConfigError, "c.cfgimpl_get_values().force_cache()")