Fix dummy translation

trans/machine/dummy.py

@@ -37,7 +37,7 @@ class DummyTranslation(MachineTranslation):
         '''
         Dummy translation supports just single phrase.
         '''
-        if text.strip == 'Hello, world!':
+        if text.strip() == 'Hello, world!':
             return [
                 'Nazdar světe!',
                 'Ahoj světe!',

trans/tests/machine.py

@@ -48,7 +48,7 @@ class MachineTranslationTest(TestCase):
         )
         self.assertEqual(
             machine_translation.translate('cs', 'Hello, world!'),
-            []
+            ['Nazdar světe!', 'Ahoj světe!']
         )
 
     def test_glosbe(self):