diff --git a/core/tests/test_pm3argparse.py b/core/tests/test_pm3argparse.py
index c8c54c5924c72a435fc1ee48a76bb1e5e11037f9..948d20f116f10c8689aac474f1541167907ba1ca 100644
--- a/core/tests/test_pm3argparse.py
+++ b/core/tests/test_pm3argparse.py
@@ -77,6 +77,32 @@ class PM3ArgParseTests(unittest.TestCase):
                           'test.\n\noptional arguments:\n  -h, --help  show '+
                           'this help message and exit'])
 
+    def testAddAlignmentNoTrgArg(self):
+        # check failure on missing trg: argument
+        parser = pm3argparse.PM3ArgumentParser(__doc__, action=False)
+        parser.AddAlignment()
+        parser.AssembleParser()
+        with self.assertRaises(SystemExit) as ecd:
+            parser.Parse(['--fasta', 'data/fasta/alignment.fas'])
+        self.assertEqual(ecd.exception.code, 2)
+        self.assertEqual(self.log.messages['ERROR'],
+                         ['usage: test_pm3argparse.py [-h] [-f trg:<NAME> '+
+                          '<FILE>]', 'test_pm3argparse.py: error: argument '+
+                          '-f/--fasta: expected 2 argument(s)'])
+
+    def testAddAlignmentNoFileArg(self):
+        # check failure on missing file argument
+        parser = pm3argparse.PM3ArgumentParser(__doc__, action=False)
+        parser.AddAlignment()
+        parser.AssembleParser()
+        with self.assertRaises(SystemExit) as ecd:
+            parser.Parse(['--fasta', 'trg:target'])
+        self.assertEqual(ecd.exception.code, 2)
+        self.assertEqual(self.log.messages['ERROR'],
+                         ['usage: test_pm3argparse.py [-h] [-f trg:<NAME> '+
+                          '<FILE>]', 'test_pm3argparse.py: error: argument '+
+                          '-f/--fasta: expected 2 argument(s)'])
+
     def testAddAlignemntNoTrgPfx(self):
         # checking that we fail on missing 'trg:' prefix for arguments of
         # --fasta