Update test_change_sample_rate

If we are going to use the self_sample_rate property
introduced, then the setting of sample rate should be
done via self._sample_rate.

The sample_rate setter should be checked for coverage, and
possbly modified.

Will add notes to issue #171

tests/timeseries/test_channel_ts.py

@@ -2,7 +2,7 @@
 """
 Created on Fri Jan 22 12:32:55 2021
 
-:copyright: 
+:copyright:
     Jared Peacock ([email protected])
 
 :license: MIT
@@ -364,7 +364,7 @@ def test_change_sample_rate(self):
 
         with self.subTest(name="sample_interval"):
             self.assertEqual(self.ts.sample_interval, 1.0 / 16.0)
-        self.ts.sample_rate = 8
+        self.ts._sample_rate = 8
         with self.subTest("8"):
             self.assertEqual(self.ts.sample_rate, 8.0)
         with self.subTest("n_samples"):