Added test for extra decimal places for subsecond strings

Author: Jesse Harwin

tests/duration/test_in_words.py

@@ -65,9 +65,14 @@ def test_subseconds():
     assert pi.in_words() == "0.12 seconds"
 
 
+def test_subseconds_with_n_digits():
+    pi = pendulum.duration(microseconds=123456)
+
+    assert pi.in_words(seconds_n_decimal=3) == "0.123 seconds"
+
+
 def test_subseconds_with_seconds():
     pi = pendulum.duration(seconds=12, microseconds=123456)
-
     assert pi.in_words() == "12 seconds"