Fix pluralization of "seconds" in test output

[loganrosen]

Fixing the pluralization of "seconds" in the test output so that instead of saying "1 seconds" it says "1 second," while maintaining the plural for other numbers.

Checklist

• Feature branch is up-to-date with master (if not - rebase it).
• Added tests.
• Added an entry to the Changelog if the new
  code introduces user-observable changes.
• Update Readme.md when cli options are changed

[grosser]

thx, will be in whatever the next release is