|Johnny Test 2004|
A pilot was produced in 2004, a full year before Kids' WB picked it up as a full series. Very little is known about the pilot, other than the fact that Johnny, Dukey (who was referred to as Poochie at the time), Mary, Susan, their parents, Hugh and Lila, and Bling-Bling Boy (referred as Golden Boy and had a different design) all appeared in the pilot. According to TV.com user DerekIam, the pilot was animated in Flash unlike Season 1 (Which is animated at Warner Bros. at the time), it contained a American cast (unlike the rest of the series, which is mainly Canadian, with James Arnold Taylor retained as Johnny), and that the pilot was redone as the first episode of the series.
Only a screenshot from the pilot exists online. There is currently no video footage and screenshots other than the aforementioned.
04/15/16 Update: Lost Media user MikeTuzick has found the promo for the pilot aired in 2005, thanks man.