tests: news: check if an invalid item is caught

Bug: https://bugs.gentoo.org/889330
Signed-off-by: Sam James <sam@gentoo.org>

lib/portage/tests/news/test_NewsItem.py

@@ -135,7 +135,11 @@ def testBasicNewsItem(self):
         # Simple test with no filter fields (Display-If-*)
         item = self._createNewsItem()
         self.assertTrue(item.isValid())
-        # relevant: self.assertTrue(...)
+        self.assertTrue(item.isRelevant(self.vardb, self.settings, self.profile))
+
+        # Does an invalid item fail? ("a" is not a valid package name)
+        item = self._createNewsItem({"display_if_installed": "a"})
+        self.assertFalse(item.isValid())
 
     def testDisplayIfProfile(self):
         # First, just check the simple case of one profile matching ours.