add broken test

pkg/expr/mongo_test.go

@@ -29,6 +29,7 @@ func TestConvertToMongo(t *testing.T) {
 	}{
 		{"equal", "s == 3", nil, bson.M{"s": 3}, false},
 		{"in array", "s in [1,2,3]", nil, bson.M{"s": bson.M{"$in": []interface{}{1, 2, 3}}}, false},
+		{"not in array", "s not in [1,2,3]", nil, bson.M{"s": bson.M{"$nin": []interface{}{1, 2, 3}}}, false},
 		{"contains", "s contains 'some'", nil, bson.M{"s": bson.M{"$regex": "some"}}, false},
 		{"contains with . + () $ {} ^", "value contains 'something with . + () $ {} ^'", nil, bson.M{"value": bson.M{"$regex": "something with \\. \\+ \\(\\) \\$ \\{\\} \\^"}}, false},
 		{"startsWith", "s startsWith 'some'", nil, bson.M{"s": bson.M{"$regex": "^some.*"}}, false},