AMBARI-3620. Ambari server setup-security kerberos jaas configuration accepts directory path as keytab path (dsen)

ambari-server/src/main/python/ambari-server.py

@@ -3665,7 +3665,7 @@ def get_fqdn():
 
 
 def is_valid_filepath(filepath):
-  if not filepath or not os.path.exists(filepath):
+  if not filepath or not os.path.exists(filepath) or os.path.isdir(filepath):
     print 'Invalid path, please provide the absolute file path.'
     return False
   else:

ambari-server/src/test/python/TestAmbariServer.py

@@ -4255,3 +4255,36 @@ MIIFHjCCAwYCCQDpHKOBI+Lt0zANBgkqhkiG9w0BAQUFADBRMQswCQYDVQQGEwJV
 
     del os.environ[ambari_server.AMBARI_CONF_VAR]
     os.remove(prop_file)
+
+
+  def test_is_valid_filepath(self):
+    temp_dir = tempfile.gettempdir()
+    temp_file = tempfile.NamedTemporaryFile(mode='r')
+
+    # Correct path to an existing file
+    self.assertTrue(temp_file)
+    # Correct path to an existing directory
+    self.assertFalse(ambari_server.is_valid_filepath(temp_dir), \
+      'is_valid_filepath(path) should return False is path is a directory')
+    # Incorrect path
+    self.assertFalse(ambari_server.is_valid_filepath(''))
+
+  @patch.object(ambari_server, "search_file")
+  @patch.object(ambari_server, "get_validated_string_input")
+  def test_setup_ambari_krb5_jaas(self, get_validated_string_input_mock,
+                                  search_file_mock):
+    search_file_mock.return_value = ''
+
+    # Should raise exception if jaas_conf_file isn't an existing file
+    self.assertRaises(NonFatalException, ambari_server.setup_ambari_krb5_jaas)
+
+    temp_file = tempfile.NamedTemporaryFile(mode='r')
+    search_file_mock.return_value = temp_file.name
+    get_validated_string_input_mock.side_effect = ['adm@EXAMPLE.COM', temp_file]
+
+    # setup_ambari_krb5_jaas() should return None if everything is OK
+    self.assertIsNone(ambari_server.setup_ambari_krb5_jaas())
+    self.assertTrue(get_validated_string_input_mock.called)
+    self.assertEqual(get_validated_string_input_mock.call_count, 2)
+
+