diff --git a/tests/test_mets.py b/tests/test_mets.py
index d089549..c14fa26 100644
--- a/tests/test_mets.py
+++ b/tests/test_mets.py
@@ -581,8 +581,19 @@ def test_parse_production_pointer_file(self):
 
     def assert_mets_valid(self, mets_doc, schematron=metsrw.AM_SCT_PATH):
         is_valid, report = metsrw.validate(mets_doc, schematron=schematron)
-        if not is_valid:
+        try:
+            assert is_valid
+        except AssertionError:
             raise AssertionError(report['report'])
 
     def assert_pointer_valid(self, mets_doc):
         self.assert_mets_valid(mets_doc, schematron=metsrw.AM_PNTR_SCT_PATH)
+
+
+def test_invalid_mets_file():
+    mets_path = 'fixtures/mets_without_groupid_in_file.xml'
+    mets_doc = etree.parse(mets_path)
+    schematron = metsrw.AM_SCT_PATH
+    is_valid, report = metsrw.validate(mets_doc, schematron=schematron)
+    assert not is_valid
+    assert 'An amdSec element MUST contain a techMD' in report['report']
diff --git a/tests/test_validate.py b/tests/test_validate.py
index ee4a307..dfb340f 100644
--- a/tests/test_validate.py
+++ b/tests/test_validate.py
@@ -22,3 +22,12 @@ def test_get_schematron(mocker):
         with pytest.raises(IOError):
             metsrw.get_schematron(bad_path)
             get_file_path.assert_called_once_with(bad_path)
+
+    def mockisfile(path):
+        if path == bad_path:
+            return False
+        return True
+    mocker.patch.object(os.path, 'isfile', mockisfile)
+    with pytest.raises(IOError):
+        metsrw.get_schematron(bad_path)
+        assert os.path.isfile.call_count == 2