The following doesn't work and it worked before in 1.10:

/scoreboard teams add Test
/scoreboard players join Test @e

/testfor @e[team=Test]

It's supposed to output all items, currently loaded in that team, but it doesn't work anymore.

When I add myself to the same team and ONLY change @e to @a, it works.

EDIT: After a bit more of testing, using @e only shows players on a scoreboard team.