Add truncated and ancient wtmp example to tests

A too-small file can't contain something useful.

Also, a wtmp file with a timestamp from pre-2000 is beyond what you'd
expect on a 2021 system.

utils/test/test-notify.py

@@ -12,6 +12,7 @@
 import unittest
 from common_test import AATest, setup_all_loops
 
+from apparmor.common import AppArmorBug
 from apparmor.notify import get_last_login_timestamp
 
 class TestGet_last_login_timestamp(AATest):
@@ -23,6 +24,8 @@ class TestGet_last_login_timestamp(AATest):
         (['wtmp-s390x',         'whoever'   ], 0),
         (['wtmp-aarch64',       'guillaume' ], 1611562789),  # Mon Jan 25 09:19:49 CET 2021
         (['wtmp-aarch64',       'whoever'   ], 0),
+        (['wtmp-truncated',     'root'      ], 0),
+        (['wtmp-truncated',     'whoever'   ], 0),
     ]
 
     def _run_test(self, params, expected):
@@ -30,6 +33,11 @@ class TestGet_last_login_timestamp(AATest):
         filename = 'wtmp-examples/%s' % filename
         self.assertEqual(get_last_login_timestamp(user, filename), expected)
 
+    def test_date_1999(self):
+        with self.assertRaises(AppArmorBug):
+            # wtmp-x86_64-past is hand-edited to Thu Dec 30 00:00:00 CET 1999, which is outside the expected data range
+            get_last_login_timestamp('root', 'wtmp-examples/wtmp-x86_64-past')
+
 
 setup_all_loops(__name__)
 if __name__ == '__main__':

utils/test/wtmp-examples/wtmp-x86_64-past-expected

@@ -0,0 +1,3 @@
+root     pts/0        blast.from.the.p Thu Dec 30 00:00    gone - no logout
+
+wtmp-x86_64-past begins Thu Dec 30 00:00:00 1999