Test failure with QuickCheck 2.14.3

```
      Seconds truncate is Nano truncate:                                    FAIL
        *** Failed! Falsified (after 5 tests):
        -1.000000000
        Use --quickcheck-replay=391660 to reproduce.
        Use -p '/Seconds truncate is Nano truncate/' to rerun this test only.
```

It passes with QuickCheck 2.14.2 or older versions, with everything else unchanged.