diff --git a/tests/test_series/test_series.py b/tests/test_series/test_series.py
index 1ee2f7d0360d029689c5aaab87656e585a0a990f..833ce84996eee8db3c32b649628ffda4d8d7d227 100644
--- a/tests/test_series/test_series.py
+++ b/tests/test_series/test_series.py
@@ -10,3 +10,6 @@ class TestSeries(unittest.TestCase):
 
         ds = DataSeries()
         self.assertAlmostEqual(ds.length(), 0.0)
+
+        ds = DataSeries([[0,1], [10,2]])
+        self.assertAlmostEqual(ds.length(), 10.0)