Conversation so far:
What big event happened in 1988 to make Testament so popular?
Was Testament a one member band?
Eric Peterson, Chuck Billy, Alex Skolnick, Gene Hoglan, and Steve Di Giorgio are the members of Testament.
Did Testament have more than one album?
Testament has twelve albums.
Did Testament have an album that topped the music charts?
Dark Roots of Earth debuted at No. 12 on the Billboard 200, the band's highest chart position to date.
Did Testament have more than one song that came from their Roots album?

Question: Did they have any band members leave during the period they were most popular?
Self-contained rewrite: Did Testament have any band members leave during the period they were most popular?