internal/core/adt: add tests for Issue 4000
Issue #4000
Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com>
Change-Id: I1e50302bf165e002149d6cb33c570d7605e36f5e
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1219236
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>