diff --git a/pymisp/api.py b/pymisp/api.py
index 6b265e9..a0d285e 100644
--- a/pymisp/api.py
+++ b/pymisp/api.py
@@ -190,8 +190,11 @@ class PyMISP(object):
         messages = []
         if response.get('error'):
             if isinstance(response['error'], list):
-                for e in response['errors']:
-                    messages.append(e['error']['value'][0])
+                for e in response['error']:
+                    if isinstance(e, dict):
+                        messages.append(e['error']['value'][0])
+                    else:
+                        messages.append(e)
             else:
                 messages.append(['error'])
         elif response.get('errors'):
diff --git a/tests/test_offline.py b/tests/test_offline.py
index e2d0c9c..15f99b0 100644
--- a/tests/test_offline.py
+++ b/tests/test_offline.py
@@ -51,6 +51,13 @@ class TestOffline(unittest.TestCase):
         m.register_uri('DELETE', self.domain + 'events/3', json={'errors': ['Invalid event'], 'message': 'Invalid event', 'name': 'Invalid event', 'url': '/events/3'})
         m.register_uri('GET', self.domain + 'attributes/delete/2', json={'message': 'Attribute deleted.'})
         m.register_uri('POST', self.domain + 'events/index', json=self.search_index_result)
+        m.register_uri('POST', self.domain + 'attributes/edit/' + self.key, json={})
+        m.register_uri('GET', self.domain + 'shadow_attributes/view/None', json={})
+        m.register_uri('GET', self.domain + 'shadow_attributes/view/1', json={})
+        m.register_uri('POST', self.domain + 'events/freeTextImport/1', json={})
+        m.register_uri('POST', self.domain + 'attributes/restSearch', json={})
+        m.register_uri('POST', self.domain + 'attributes/downloadSample', json={})
+        m.register_uri('GET', self.domain + 'tags', json={'Tag': 'foo'})
 
     def test_getEvent(self, m):
         self.initURI(m)
@@ -297,6 +304,97 @@ class TestOffline(unittest.TestCase):
             self.assertTrue(sd['to_ids'] in [0, 1])
             self.assertTrue(sd['default_category'] in categories)
 
+    def test_flatten_error_messages_singular(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        error = pymisp.get(1)
+        response = self.auth_error_msg
+        response['error'] = ['foo', 'bar', 'baz']
+        messages = pymisp.flatten_error_messages(response)
+        self.assertEqual(["foo", "bar", "baz"], messages)
+
+    def test_flatten_error_messages_plural(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        error = pymisp.get(1)
+        response = self.auth_error_msg
+        response['errors'] = {'foo': 42, 'bar': False, 'baz': ['oo', 'ka']}
+        messages = pymisp.flatten_error_messages(response)
+        self.assertEqual(set(['42 (foo)', 'False (bar)', 'oo', 'ka']), set(messages))
+
+    def test_flatten_error_messages_nested(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        error = pymisp.get(1)
+        response = self.auth_error_msg
+        response['errors'] = {
+            'fo': {'o': 42}, 'ba': {'r': True}, 'b': {'a': ['z']}, 'd': {'e': {'e': ['p']}}}
+        messages = pymisp.flatten_error_messages(response)
+        self.assertEqual(set(['Error in o: 42', 'Error in r: True', 'Error in a: z', "Error in e: {'e': ['p']}"]), set(messages))
+
+    def test_test_connection(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertTrue(pymisp.test_connection())
+
+    def test_change_toids(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertEqual({}, pymisp.change_toids(self.key, 1))
+
+    def test_change_toids_invalid(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        try:
+            _ = pymisp.change_toids(self.key, 42)
+            self.assertFalse('Exception required for off domain value')
+        except Exception:
+            pass
+
+    def test_proposal_view_default(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertEqual({}, pymisp.proposal_view())
+
+    def test_proposal_view_event_1(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertEqual({}, pymisp.proposal_view(event_id=1))
+
+    def test_proposal_view_event_overdetermined(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertTrue(pymisp.proposal_view(event_id=1, proposal_id=42).get('error') is not None)
+
+    def test_freetext(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertEqual({}, pymisp.freetext(1, 'foo', adhereToWarninglists=True, distribution=42))
+
+    def test_freetext_offdomain(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        try:
+            _ = pymisp.freetext(1, None, adhereToWarninglists='hard')
+            self.assertFalse('Exception required for off domain value')
+        except Exception:
+            pass
+
+    def test_get_yara(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertEqual((False, None), pymisp.get_yara(1))
+
+    def test_download_samples(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertEqual((False, None), pymisp.download_samples())
+
+    def test_get_all_tags(self, m):
+        self.initURI(m)
+        pymisp = PyMISP(self.domain, self.key)
+        self.assertEqual({'Tag': 'foo'}, pymisp.get_all_tags())
+
 
 if __name__ == '__main__':
     unittest.main()