From wiki.mozilla.org

  • Pretend you're writing a bug - it's pretty much the same
  • Assume that the person following your test case only has basic familiarity with the product. For example:
    • "Bring up the New Calendar Wizard" - This is too vague.
    • "Launch the New Calendar Dialog (by either double clicking calendar list, File->New Calendar or right clicking calendar list)." - This is much better.
  • Be fairly specific with the expected results
    • "It worked" - Once again, too vague.
    • "The event was created on the proper day; The event had the proper color" - This is great.
  • Keep list of steps and expected results as simple as possible.
  • You don't need to detail every click unless it's an important part of the testcase.
    • Click on the name text box; enter a name. Click on Color drop down, pick red.-- This is a little much
    • Give the calendar a name, assign it a color. --This is much better.

Christopher McMahon mentioned this at agile-testing@yahoogroups.com.