Bulk Update Multiple Work Item Resolutions

// The Name of the resolution to be set
def resolutionName = 'Cannot Reproduce'

// Get all work items matching the specified JQL Query
WorkItems.search("project = TEST AND issueType = Bug").each { workItem ->
    workItem.transition('Done') {
        setResolution(resolutionName)
    }
    logger.info("Resolution set to ${resolutionName} for the ${workItem.key} work item")
}