For years now, I've held the belief that effective automated test suites have four essential attributes. These attributes have been referenced by other authors, and were the subject of a talk I gave at the Agile 2009 conference. But I was shocked to discover (that is, remember) that the only place they are formally documented is in my Continuous Testing book [Pragmatic Bookshelf, 2011], which is now out of date, out of print, and totally inaccessible to most of the Internet. And so, I'm capturing these four attributes here. I intend to treat this as a living document, updating it as my understanding of these attributes evolves.