assertNotNull("found no GrammarInsufficientPredicatesMessage alts; expecting: "+
str(expectingNonDetAlts), insuffPredMsg);
Map<Integer, Set<Token>> locations = insuffPredMsg.altToLocations;
Set<Integer> actualAlts = locations.keySet();
BitSet s = new BitSet();
s.addAll(expectingInsufficientPredAlts);
BitSet s2 = new BitSet();
s2.addAll(actualAlts);
assertEquals("mismatch between insufficiently covered alts", s, s2);
assertEquals("mismatch between expected hasPredHiddenByAction", hasPredHiddenByAction,
insuffPredMsg.problemState.dfa.hasPredicateBlockedByAction);