test: added additional tests for single value, no value and null values
test: added additional tests for single value, no value and null values

Signed-off-by: Manan Gupta <78fb1e040152fc0d289292783ed01a56d3ae9465@planetscale.com>

vitessio/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,mahak/vitess