}

    def "method putAll() reports argument as change only"() {
        when:
        def update = [existing: 'changedExisting', missing: 'changedMissing']
        getMapUnderTestToWrite().putAll(update)

        then:
        1 * onChange.accept('existing', 'changedExisting')
        1 * onChange.accept('missing', 'changedMissing')
        0 * onAccess._
    }