I always use "test" and never "[" (and I've only used "[[" once when I thought I needed a builtin regex matcher for efficiency). Partly because fish does the same, partly because despite writing bash scripts for years I do not want to have the "[ vs [[" information in my brain (nor should whoever reads my code).

(For similar reasons, whenever I'm grepping for a nontrivial regex, I always use egrep rather than grep, because the escaping semantics are simpler—"if it's escaped with a \, then it's not special"—and again I do not want to have the information of "which characters are special only when escaped in base grep" in my brain.)