TST: Add unittest for empty arrays

unittests/test_table_importer.py

@@ -181,6 +181,15 @@ class TableImporterTest(unittest.TestCase):
         self.assertEqual(df_new.shape[1], 4)
         self.assertEqual(df_new.iloc[0].b, 5)
 
+        # check that missing array-valued fields are detected correctly:
+        df = pd.DataFrame([[[None, None], 4, 2.0, 'yes'],
+                           ['b', 5, 3.0, 'no']],
+                          columns=['a', 'b', 'c', 'd'])
+        df_new = importer.check_missing(df)
+        self.assertEqual(df_new.shape[0], 1)
+        self.assertEqual(df_new.shape[1], 4)
+        self.assertEqual(df_new.iloc[0].b, 5)
+
     def test_wrong_datatype(self):
         importer = TableImporter(**self.importer_kwargs)
         df = pd.DataFrame([[None, np.nan, 2.0, 'yes'],