func waitForNUnitsStart(cl platform.Cluster, m platform.Member, nu int) (map[string][]util.UnitState, error) {
	listUnitStates, err := cl.WaitForNActiveUnits(m, nu)
	if err != nil {
		return nil, fmt.Errorf("Failed to run list-units: %v", err)
	}
	return listUnitStates, nil
}

func waitForNUnitsSubmit(cl platform.Cluster, m platform.Member, nu int) (map[string][]util.UnitFileState, error) {
	// wait until the unit gets processed up to 15 seconds
	listUnitStates, err := cl.WaitForNUnitFiles(m, nu)
	if err != nil {
		return nil, fmt.Errorf("Failed to run list-unit-files: %v", err)
	}
	return listUnitStates, nil
}

func cleanUnits(cl platform.Cluster, m platform.Member, cmd string, ufs []string, nu int) (err error) {
	for i := 0; i < nu; i++ {
		if _, _, err := cl.Fleetctl(m, cmd, ufs[i]); err != nil {
			return fmt.Errorf("Failed to %s unit: %v", cmd, err)
		}
	}
	return nil
}

// waitForFleetdSocket returns if /var/run/fleet.sock exists, periodically
// checking for states.
func waitForFleetdSocket(cluster platform.Cluster, m0 platform.Member) (err error) {
	_, err = util.WaitForState(
		func() bool {
			stdout, _, _ := cluster.MemberCommand(m0, "test -S /var/run/fleet.sock && echo 1")
			if strings.TrimSpace(stdout) == "" {
				fmt.Errorf("Fleetd is not fully started, retrying...")
				return false
			}
			return true
		},
	)
	if err != nil {
		return fmt.Errorf("Fleetd socket not found: %v", err)
	}

	return nil
}

func launchUnitsCmd(cluster platform.Cluster, m platform.Member, cmd string, numUnits int) (unitFiles []string, err error) {
	args := []string{cmd}
	for i := 0; i < numUnits; i++ {
		unitFile := fmt.Sprintf("fixtures/units/[email protected]%d.service", i+1)
		args = append(args, unitFile)
		unitFiles = append(unitFiles, path.Base(unitFile))
	}

	if stdout, stderr, err := cluster.Fleetctl(m, args...); err != nil {
		return nil,
			fmt.Errorf("Unable to %s batch of units: \nstdout: %s\nstderr: %s\nerr: %v",
				cmd, stdout, stderr, err)
	} else if strings.Contains(stderr, "Error") {
		return nil,
			fmt.Errorf("Failed to correctly %s batch of units: \nstdout: %s\nstderr: %s\nerr: %v",
				cmd, stdout, stderr, err)
	}

	return unitFiles, nil
}

// waitForReloadConfig returns if a message "Reloading configuration" exists
// in the journal, periodically checking for the journal up to the timeout.
func waitForReloadConfig(cluster platform.Cluster, m0 platform.Member) (err error) {
	_, err = util.WaitForState(
		func() bool {
			// NOTE: journalctl should run just simply like "journalctl -u fleet",
			// without being piped with grep. Doing
			// "journalctl -u fleet | grep \"Reloading configuration\"" is racy
			// in a subtle way, so that it sometimes fails only on semaphoreci.
			// - dpark 20160408
			stdout, _, _ := cluster.MemberCommand(m0, "sudo", "journalctl --priority=info _PID=$(pidof fleetd)")
			journalfleet := strings.TrimSpace(stdout)
			if !strings.Contains(journalfleet, "Reloading configuration") {
				fmt.Errorf("Fleetd is not fully reconfigured, retrying... entire fleet journal:\n%v", journalfleet)
				return false
			}
			return true
		},
	)
	if err != nil {
		return fmt.Errorf("Reloading configuration log not found: %v", err)
	}

	return nil
}