Atheism can be legitimately viewed as a lack of belief, if you properly hedge your claims about whether or not it's possible for gods or other ethereal beings to exist.
Also testing a belief doesn't necessarily mean testing it in full. You've probably tested your belief in the lethality of long drops partially by falling out of trees as a child (or at least, I did).
Atheism can be legitimately viewed as a lack of belief
Not quite, that goes by the name of agnosticism. An atheist answers the question "Do gods exist?" by saying "No".
You've probably tested your belief in the lethality of long drops partially by falling out of trees as a child
The results of all these tests point out that falls are not lethal, of course :-P
Programmers do something called Test Driven Development. Basically, they write tests that say "I expect my code to do this", then write more code, and if the subsequent code they write breaks a test they wrote, they'll be notified.
Wouldn't it be cool if there was Test Driven Thinking?