diff --git a/glymur/_uuid_io.py b/glymur/_uuid_io.py
index f64baa6..bf9960a 100644
--- a/glymur/_uuid_io.py
+++ b/glymur/_uuid_io.py
@@ -101,8 +101,12 @@ class _Ifd(object):
     def parse_tag(self, dtype, count, offset_buf):
         """Interpret an Exif image tag data payload.
         """
-        fmt = self.datatype2fmt[dtype][0] * count
-        payload_size = self.datatype2fmt[dtype][1] * count
+        try:
+            fmt = self.datatype2fmt[dtype][0] * count
+            payload_size = self.datatype2fmt[dtype][1] * count
+        except KeyError:
+            msg = 'Invalid TIFF tag datatype ({0}).'.format(dtype)
+            raise IOError(msg)
 
         if payload_size <= 4:
             # Interpret the payload from the 4 bytes in the tag entry.
diff --git a/glymur/test/test_jp2box.py b/glymur/test/test_jp2box.py
index cef0d41..da5fea1 100644
--- a/glymur/test/test_jp2box.py
+++ b/glymur/test/test_jp2box.py
@@ -1332,7 +1332,6 @@ class TestRepr(unittest.TestCase):
         else:
             self.assertRegex(repr(box), regexp)
 
-    @unittest.skipIf(sys.hexversion < 0x02070000, "Requires 2.7+")
     def test_uuid_box_xmp(self):
         """Verify uuid repr method for XMP UUID box."""
         jp2file = glymur.data.nemo()
diff --git a/glymur/test/test_jp2box_uuid.py b/glymur/test/test_jp2box_uuid.py
index f24aafe..e346ade 100644
--- a/glymur/test/test_jp2box_uuid.py
+++ b/glymur/test/test_jp2box_uuid.py
@@ -138,6 +138,8 @@ class TestUUIDExif(unittest.TestCase):
                 warnings.simplefilter('always')
                 j = glymur.Jp2k(tfile.name)
                 self.assertTrue(issubclass(w[0].category, UserWarning))
+                msg = 'Invalid TIFF tag'
+                self.assertTrue(msg in str(w[0].message))
 
             self.assertEqual(j.box[-1].box_id, 'uuid')
 
diff --git a/glymur/test/test_jp2box_xml.py b/glymur/test/test_jp2box_xml.py
index 7841154..f8e2878 100644
--- a/glymur/test/test_jp2box_xml.py
+++ b/glymur/test/test_jp2box_xml.py
@@ -207,15 +207,14 @@ class TestJp2kBadXmlFile(unittest.TestCase):
     def tearDown(self):
         pass
 
-    def test_invalid_xml_box_warning(self):
-        """Should warn in case of bad XML"""
-        Jp2k(self._bad_xml_file)
-
     def test_invalid_xml_box(self):
         """Should be able to recover info from xml box with bad xml."""
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore")
+        with warnings.catch_warnings(record=True) as w:
+            warnings.simplefilter("always")
             jp2k = Jp2k(self._bad_xml_file)
+            self.assertTrue(issubclass(w[0].category, UserWarning))
+            msg = 'No XML was retrieved'
+            self.assertTrue(msg in str(w[0].message))
 
         self.assertEqual(jp2k.box[3].box_id, 'xml ')
         self.assertEqual(jp2k.box[3].offset, 77)
diff --git a/glymur/test/test_opj_suite_write.py b/glymur/test/test_opj_suite_write.py
index 861b31b..77ef262 100644
--- a/glymur/test/test_opj_suite_write.py
+++ b/glymur/test/test_opj_suite_write.py
@@ -1020,7 +1020,6 @@ class TestSuiteWrite(unittest.TestCase):
                              glymur.core.WAVELET_XFORM_5X3_REVERSIBLE)
             self.assertEqual(len(codestream.segment[2].spcod), 9)
 
-    #@unittest.skip("Known failure in openjpeg test suite.")
     def test_NR_ENC_random_issue_0005_tif_12_encode(self):
         """NR-ENC-random-issue-0005.tif-12-encode"""
         # opj_decompress has trouble reading it, but that is not an issue here.
diff --git a/glymur/test/test_printing.py b/glymur/test/test_printing.py
index 6734d01..efd1ccf 100644
--- a/glymur/test/test_printing.py
+++ b/glymur/test/test_printing.py
@@ -725,6 +725,8 @@ class TestPrintingOpjDataRoot(unittest.TestCase):
         # Reset printoptions for every test.
         glymur.set_printoptions(short=False, xml=True, codestream=True)
 
+        warnings.resetwarnings()
+
     def tearDown(self):
         pass