Given the following file (using scalatest):

package foobar

import org.junit.runner.RunWith
import org.scalatest.FunSuite
import org.scalatest.junit.JUnitRunner

@RunWith(classOf[JUnitRunner])
class FoobarSpecTest extends FunSuite {
test("basic") {
assert(true === true)
}
}

If I hit ctrl-shift-o, then the import for JUnitRunner disappears. Hitting ctrl-shift-o brings it back again. And so on.