// Check if we can scale down. We can scale down in the following 2 cases:
	// * Some old replica sets have unhealthy replicas, we could safely scale down those unhealthy replicas since that won't further
	//  increase unavailability.
	// * New replica set has scaled up and it's replicas becomes ready, then we can scale down old replica sets in a further step.
	//
	// maxScaledDown := allPodsCount - minAvailable - newReplicaSetPodsUnavailable

		return 0, nil
	}
	return intstrutil.GetScaledValueFromIntOrPercent(r.MaxSurge, numberToSchedule, true)
}

// UnavailableCount returns 0 if unavailability is not requested, the expected
// unavailability number to allow out of numberToSchedule if requested, or an error if
// the unavailability percentage requested is invalid.
func UnavailableCount(ds *apps.DaemonSet, numberToSchedule int) (int, error) {

	// event the apiserver returns 0 for both surge and unavailability)
	if desiredNumberScheduled > 0 && maxUnavailable == 0 && maxSurge == 0 {
		logger.Info("DaemonSet is not configured for surge or unavailability, defaulting to accepting unavailability", "daemonset", klog.KObj(ds))
		maxUnavailable = 1
	}

			// However, DEDUP reparse points remain similar in most respects to
			// regular files: they continue to support random-access reads and writes
			// of persistent data, and they shouldn't add unexpected latency or
			// unavailability in the way that a network filesystem might.
			//
			// Go programs may use ModeIrregular to filter out unusual files (such as
			// raw device files on Linux, POSIX FIFO special files, and so on), so

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        given:
        def availability = new ToolChainAvailability()
        availability.unavailable("some reason")

        when:
        availability.explain(visitor)

        then:
        1 * visitor.node("some reason")
    }

    def "visits message when unsupported"() {
        def visitor = Mock(DiagnosticsVisitor)

        given:
        def availability = new ToolChainAvailability()

    }

    def "getTotalPhysicalMemory fails when memory MBeans are #availability"() {
        given:
        def osMemoryInfo = createMemoryInfo(availability)

        when:
        osMemoryInfo.getOsSnapshot().getPhysicalMemory().getTotal()

        then:
        thrown UnsupportedOperationException

        where:
        availability << [MemoryAvailability.UNAVAILABLE, MemoryAvailability.INVALID_VALUE]
    }

    private ToolChainAvailability getAvailability() {
        if (availability == null) {
            availability = new ToolChainAvailability();
            checkAvailable(availability);
        }

        return availability;
    }

    private void checkAvailable(ToolChainAvailability availability) {
        if (!operatingSystem.isWindows()) {

        when:
        def availability = new ToolChainAvailability()
        toolChain.checkAvailable(availability)

        then:
        !availability.available
        availability.unavailableMessage == 'Visual Studio is not available on this operating system.'
    }