Esempio n. 1
0
// deleteVPCs ensures the given VPCs are deleted, by retrying until a
// timeout or all VPC cannot be found anymore.  This should be used to
// make sure tests leave no VPCs around.
func (s *ServerTests) deleteVPCs(c *C, ids []string) {
	testAttempt := aws.AttemptStrategy{
		Total: 2 * time.Minute,
		Delay: 5 * time.Second,
	}
	for a := testAttempt.Start(); a.Next(); {
		deleted := 0
		c.Logf("deleting VPCs %v", ids)
		for _, id := range ids {
			_, err := s.ec2.DeleteVPC(id)
			if err == nil || errorCode(err) == "InvalidVpcID.NotFound" {
				c.Logf("VPC %s deleted", id)
				deleted++
				continue
			}
			if err != nil {
				c.Logf("retrying; DeleteVPC returned: %v", err)
			}
		}
		if deleted == len(ids) {
			c.Logf("all VPCs deleted")
			return
		}
	}
	c.Fatalf("timeout while waiting %v VPCs to get deleted!", ids)
}
Esempio n. 2
0
func (s *AmazonServerSuite) waitForAddresses(c *C, nicId string, ips []string) {
	// Wait for the given IPs to appear on the NIC, retrying if needed.
	testAttempt := aws.AttemptStrategy{
		Total: 5 * time.Minute,
		Delay: 5 * time.Second,
	}
	for a := testAttempt.Start(); a.Next(); {
		c.Logf("waiting for %v IPs on NIC %v", ips, nicId)
		resp, err := s.ec2.NetworkInterfaces([]string{nicId}, nil)
		if err != nil {
			c.Logf("NetworkInterfaces returned: %v; retrying...", err)
			continue
		}
		if len(resp.Interfaces) != 1 {
			c.Logf("found %d NICs; retrying", len(resp.Interfaces))
			continue
		}
		iface := resp.Interfaces[0]
		if len(iface.PrivateIPs) != len(ips) {
			c.Logf("addresses in %v: %v; still waiting", iface.Id, iface.PrivateIPs)
			continue
		}
		for i, ip := range iface.PrivateIPs {
			c.Assert(ip.Address, Equals, ips[i])
		}
		c.Logf("all addresses updated")
		return
	}
	c.Fatalf("timeout while waiting for the IPs to get updated")
}
Esempio n. 3
0
// deleteGroups ensures the given groups are deleted, by retrying
// until a timeout or all groups cannot be found anymore.
// This should be used to make sure tests leave no groups around.
func (s *ServerTests) deleteGroups(c *C, groups []ec2.SecurityGroup) {
	testAttempt := aws.AttemptStrategy{
		Total: 2 * time.Minute,
		Delay: 5 * time.Second,
	}
	for a := testAttempt.Start(); a.Next(); {
		deleted := 0
		c.Logf("deleting groups %v", groups)
		for _, group := range groups {
			_, err := s.ec2.DeleteSecurityGroup(group)
			if err == nil || errorCode(err) == "InvalidGroup.NotFound" {
				c.Logf("group %v deleted", group)
				deleted++
				continue
			}
			if err != nil {
				c.Logf("retrying; DeleteSecurityGroup returned: %v", err)
			}
		}
		if deleted == len(groups) {
			c.Logf("all groups deleted")
			return
		}
	}
	c.Fatalf("timeout while waiting %v groups to get deleted!", groups)
}
Esempio n. 4
0
// createSubnet ensures a subnet with the given vpcId and cidrBlock
// gets created, retrying a few times with a timeout. This needs to be
// done when testing against EC2 servers, because if the VPC was just
// created it might take some time for it to show up, so the subnet
// can be created.
func (s *ServerTests) createSubnet(c *C, vpcId, cidrBlock, availZone string) *ec2.CreateSubnetResp {
	testAttempt := aws.AttemptStrategy{
		Total: 2 * time.Minute,
		Delay: 5 * time.Second,
	}
	for a := testAttempt.Start(); a.Next(); {
		resp, err := s.ec2.CreateSubnet(vpcId, cidrBlock, availZone)
		if errorCode(err) == "InvalidVpcID.NotFound" {
			c.Logf("VPC %v not created yet; retrying", vpcId)
			continue
		}
		if err != nil {
			c.Logf("retrying; CreateSubnet returned: %v", err)
			continue
		}
		return resp
	}
	c.Fatalf("timeout while waiting for VPC and subnet")
	return nil
}
Esempio n. 5
0
func (S) TestAttemptTiming(c *C) {
	testAttempt := aws.AttemptStrategy{
		Total: 0.25e9,
		Delay: 0.1e9,
	}
	want := []time.Duration{0, 0.1e9, 0.2e9, 0.2e9}
	got := make([]time.Duration, 0, len(want)) // avoid allocation when testing timing
	t0 := time.Now()
	for a := testAttempt.Start(); a.Next(); {
		got = append(got, time.Now().Sub(t0))
	}
	got = append(got, time.Now().Sub(t0))
	c.Assert(got, HasLen, len(want))
	const margin = 0.01e9
	for i, got := range want {
		lo := want[i] - margin
		hi := want[i] + margin
		if got < lo || got > hi {
			c.Errorf("attempt %d want %g got %g", i, want[i].Seconds(), got.Seconds())
		}
	}
}
Esempio n. 6
0
func terminateInstances(c *C, e *ec2.EC2, ids []string) {
	_, err := e.TerminateInstances(ids)
	c.Assert(err, IsNil, Commentf("%v INSTANCES LEFT RUNNING!!!", ids))
	// We need to wait until the instances are really off, because
	// entities that depend on them won't be deleted (i.e. groups,
	// NICs, subnets, etc.)
	testAttempt := aws.AttemptStrategy{
		Total: 10 * time.Minute,
		Delay: 5 * time.Second,
	}
	f := ec2.NewFilter()
	f.Add("instance-state-name", "terminated")
	idsLeft := make(map[string]bool)
	for _, id := range ids {
		idsLeft[id] = true
	}
	for a := testAttempt.Start(); a.Next(); {
		c.Logf("waiting for %v to get terminated", ids)
		resp, err := e.Instances(ids, f)
		if err != nil {
			c.Fatalf("not waiting for %v to terminate: %v", ids, err)
		}
		for _, r := range resp.Reservations {
			for _, inst := range r.Instances {
				delete(idsLeft, inst.InstanceId)
			}
		}
		ids = []string{}
		for id, _ := range idsLeft {
			ids = append(ids, id)
		}
		if len(ids) == 0 {
			c.Logf("all instances terminated.")
			return
		}
	}
	c.Fatalf("%v INSTANCES LEFT RUNNING!!!", ids)
}
func (s *ServerTests) TestNetworkInterfaces(c *C) {
	vpcResp, err := s.ec2.CreateVPC("10.3.0.0/16", "")
	c.Assert(err, IsNil)
	vpcId := vpcResp.VPC.Id
	defer s.deleteVPCs(c, []string{vpcId})

	subResp := s.createSubnet(c, vpcId, "10.3.1.0/24", "")
	subId := subResp.Subnet.Id
	defer s.deleteSubnets(c, []string{subId})

	sg := s.makeTestGroupVPC(c, vpcId, "vpc-sg-1", "vpc test group1")
	defer s.deleteGroups(c, []ec2.SecurityGroup{sg})

	instList, err := s.ec2.RunInstances(&ec2.RunInstances{
		ImageId:      imageId,
		InstanceType: "t1.micro",
		SubnetId:     subId,
	})
	c.Assert(err, IsNil)
	inst := instList.Instances[0]
	c.Assert(inst, NotNil)
	instId := inst.InstanceId
	defer terminateInstances(c, s.ec2, []string{instId})

	ips1 := []ec2.PrivateIP{{Address: "10.3.1.10", IsPrimary: true}}
	resp1, err := s.ec2.CreateNetworkInterface(ec2.CreateNetworkInterface{
		SubnetId:    subId,
		PrivateIPs:  ips1,
		Description: "My first iface",
	})
	c.Assert(err, IsNil)
	assertNetworkInterface(c, resp1.NetworkInterface, "", subId, ips1)
	c.Check(resp1.NetworkInterface.Description, Equals, "My first iface")
	id1 := resp1.NetworkInterface.Id

	ips2 := []ec2.PrivateIP{
		{Address: "10.3.1.20", IsPrimary: true},
		{Address: "10.3.1.22", IsPrimary: false},
	}
	resp2, err := s.ec2.CreateNetworkInterface(ec2.CreateNetworkInterface{
		SubnetId:         subId,
		PrivateIPs:       ips2,
		SecurityGroupIds: []string{sg.Id},
	})
	c.Assert(err, IsNil)
	assertNetworkInterface(c, resp2.NetworkInterface, "", subId, ips2)
	c.Assert(resp2.NetworkInterface.Groups, DeepEquals, []ec2.SecurityGroup{sg})
	id2 := resp2.NetworkInterface.Id

	// We only check for the network interfaces we just created,
	// because the user might have others in his account (when testing
	// against the EC2 servers). In some cases it takes a short while
	// until both interfaces are created, so we need to retry a few
	// times to make sure.
	testAttempt := aws.AttemptStrategy{
		Total: 5 * time.Minute,
		Delay: 5 * time.Second,
	}
	var list *ec2.NetworkInterfacesResp
	done := false
	for a := testAttempt.Start(); a.Next(); {
		c.Logf("waiting for %v to be created", []string{id1, id2})
		list, err = s.ec2.NetworkInterfaces(nil, nil)
		if err != nil {
			c.Logf("retrying; NetworkInterfaces returned: %v", err)
			continue
		}
		found := 0
		for _, iface := range list.Interfaces {
			c.Logf("found NIC %v", iface)
			switch iface.Id {
			case id1:
				assertNetworkInterface(c, iface, id1, subId, ips1)
				found++
			case id2:
				assertNetworkInterface(c, iface, id2, subId, ips2)
				found++
			}
			if found == 2 {
				done = true
				break
			}
		}
		if done {
			c.Logf("all NICs were created")
			break
		}
	}
	if !done {
		c.Fatalf("timeout while waiting for NICs %v", []string{id1, id2})
	}

	list, err = s.ec2.NetworkInterfaces([]string{id1}, nil)
	c.Assert(err, IsNil)
	c.Assert(list.Interfaces, HasLen, 1)
	assertNetworkInterface(c, list.Interfaces[0], id1, subId, ips1)

	f := ec2.NewFilter()
	f.Add("network-interface-id", id2)
	list, err = s.ec2.NetworkInterfaces(nil, f)
	c.Assert(err, IsNil)
	c.Assert(list.Interfaces, HasLen, 1)
	assertNetworkInterface(c, list.Interfaces[0], id2, subId, ips2)

	// Attachment might fail if the instance is not running yet,
	// so we retry for a while until it succeeds.
	var attResp *ec2.AttachNetworkInterfaceResp
	for a := testAttempt.Start(); a.Next(); {
		attResp, err = s.ec2.AttachNetworkInterface(id2, instId, 1)
		if err != nil {
			c.Logf("AttachNetworkInterface returned: %v; retrying...", err)
			attResp = nil
			continue
		}
		c.Logf("AttachNetworkInterface succeeded")
		c.Check(attResp.AttachmentId, Not(Equals), "")
		break
	}
	if attResp == nil {
		c.Fatalf("timeout while waiting for AttachNetworkInterface to succeed")
	}

	list, err = s.ec2.NetworkInterfaces([]string{id2}, nil)
	c.Assert(err, IsNil)
	att := list.Interfaces[0].Attachment
	c.Check(att.Id, Equals, attResp.AttachmentId)
	c.Check(att.InstanceId, Equals, instId)
	c.Check(att.DeviceIndex, Equals, 1)
	c.Check(att.Status, Matches, "(attaching|in-use)")

	_, err = s.ec2.DetachNetworkInterface(att.Id, true)
	c.Check(err, IsNil)

	_, err = s.ec2.DeleteNetworkInterface(id1)
	c.Assert(err, IsNil)

	// We might not be able to delete the interface until the
	// detachment is completed, so we need to retry here as well.
	for a := testAttempt.Start(); a.Next(); {
		_, err = s.ec2.DeleteNetworkInterface(id2)
		if err != nil {
			c.Logf("DeleteNetworkInterface returned: %v; retrying...", err)
			continue
		}
		c.Logf("DeleteNetworkInterface succeeded")
		return
	}
	c.Fatalf("timeout while waiting for DeleteNetworkInterface to succeed")
}
Esempio n. 8
0
func (s *ServerTests) TestVPCs(c *C) {
	resp1, err := s.ec2.CreateVPC("10.0.0.0/16", "")
	c.Assert(err, IsNil)
	assertVPC(c, resp1.VPC, "", "10.0.0.0/16")
	id1 := resp1.VPC.Id

	resp2, err := s.ec2.CreateVPC("10.1.0.0/16", "default")
	c.Assert(err, IsNil)
	assertVPC(c, resp2.VPC, "", "10.1.0.0/16")
	id2 := resp2.VPC.Id

	// We only check for the VPCs we just created, because the user
	// might have others in his account (when testing against the EC2
	// servers). In some cases it takes a short while until both VPCs
	// are created, so we need to retry a few times to make sure.
	var list *ec2.VPCsResp
	done := false
	testAttempt := aws.AttemptStrategy{
		Total: 2 * time.Minute,
		Delay: 5 * time.Second,
	}
	for a := testAttempt.Start(); a.Next(); {
		c.Logf("waiting for %v to be created", []string{id1, id2})
		list, err = s.ec2.VPCs(nil, nil)
		if err != nil {
			c.Logf("retrying; VPCs returned: %v", err)
			continue
		}
		found := 0
		for _, vpc := range list.VPCs {
			c.Logf("found VPC %v", vpc)
			switch vpc.Id {
			case id1:
				assertVPC(c, vpc, id1, resp1.VPC.CIDRBlock)
				found++
			case id2:
				assertVPC(c, vpc, id2, resp2.VPC.CIDRBlock)
				found++
			}
			if found == 2 {
				done = true
				break
			}
		}
		if done {
			c.Logf("all VPCs were created")
			break
		}
	}
	if !done {
		c.Fatalf("timeout while waiting for VPCs %v", []string{id1, id2})
	}

	list, err = s.ec2.VPCs([]string{id1}, nil)
	c.Assert(err, IsNil)
	c.Assert(list.VPCs, HasLen, 1)
	assertVPC(c, list.VPCs[0], id1, resp1.VPC.CIDRBlock)

	f := ec2.NewFilter()
	f.Add("cidr", resp2.VPC.CIDRBlock)
	list, err = s.ec2.VPCs(nil, f)
	c.Assert(err, IsNil)
	c.Assert(list.VPCs, HasLen, 1)
	assertVPC(c, list.VPCs[0], id2, resp2.VPC.CIDRBlock)

	_, err = s.ec2.DeleteVPC(id1)
	c.Assert(err, IsNil)
	_, err = s.ec2.DeleteVPC(id2)
	c.Assert(err, IsNil)
}
Esempio n. 9
0
func (s *ServerTests) TestSubnets(c *C) {
	resp, err := s.ec2.CreateVPC("10.2.0.0/16", "")
	c.Assert(err, IsNil)
	vpcId := resp.VPC.Id
	defer s.deleteVPCs(c, []string{vpcId})

	resp1 := s.createSubnet(c, vpcId, "10.2.1.0/24", "")
	assertSubnet(c, resp1.Subnet, "", vpcId, "10.2.1.0/24")
	id1 := resp1.Subnet.Id

	resp2, err := s.ec2.CreateSubnet(vpcId, "10.2.2.0/24", "")
	c.Assert(err, IsNil)
	assertSubnet(c, resp2.Subnet, "", vpcId, "10.2.2.0/24")
	id2 := resp2.Subnet.Id

	// We only check for the subnets we just created, because the user
	// might have others in his account (when testing against the EC2
	// servers). In some cases it takes a short while until both
	// subnets are created, so we need to retry a few times to make
	// sure.
	testAttempt := aws.AttemptStrategy{
		Total: 2 * time.Minute,
		Delay: 5 * time.Second,
	}
	var list *ec2.SubnetsResp
	done := false
	for a := testAttempt.Start(); a.Next(); {
		c.Logf("waiting for %v to be created", []string{id1, id2})
		list, err = s.ec2.Subnets(nil, nil)
		if err != nil {
			c.Logf("retrying; Subnets returned: %v", err)
			continue
		}
		found := 0
		for _, subnet := range list.Subnets {
			c.Logf("found subnet %v", subnet)
			switch subnet.Id {
			case id1:
				assertSubnet(c, subnet, id1, vpcId, resp1.Subnet.CIDRBlock)
				found++
			case id2:
				assertSubnet(c, subnet, id2, vpcId, resp2.Subnet.CIDRBlock)
				found++
			}
			if found == 2 {
				done = true
				break
			}
		}
		if done {
			c.Logf("all subnets were created")
			break
		}
	}
	if !done {
		c.Fatalf("timeout while waiting for subnets %v", []string{id1, id2})
	}

	list, err = s.ec2.Subnets([]string{id1}, nil)
	c.Assert(err, IsNil)
	c.Assert(list.Subnets, HasLen, 1)
	assertSubnet(c, list.Subnets[0], id1, vpcId, resp1.Subnet.CIDRBlock)

	f := ec2.NewFilter()
	f.Add("cidr", resp2.Subnet.CIDRBlock)
	list, err = s.ec2.Subnets(nil, f)
	c.Assert(err, IsNil)
	c.Assert(list.Subnets, HasLen, 1)
	assertSubnet(c, list.Subnets[0], id2, vpcId, resp2.Subnet.CIDRBlock)

	_, err = s.ec2.DeleteSubnet(id1)
	c.Assert(err, IsNil)
	_, err = s.ec2.DeleteSubnet(id2)
	c.Assert(err, IsNil)
}
Esempio n. 10
0
func (s *AmazonServerSuite) TestRunInstancesVPC(c *C) {
	vpcResp, err := s.ec2.CreateVPC("10.6.0.0/16", "")
	c.Assert(err, IsNil)
	vpcId := vpcResp.VPC.Id
	defer s.deleteVPCs(c, []string{vpcId})

	subResp := s.createSubnet(c, vpcId, "10.6.1.0/24", "")
	subId := subResp.Subnet.Id
	defer s.deleteSubnets(c, []string{subId})

	groupResp, err := s.ec2.CreateSecurityGroupVPC(
		vpcId,
		sessionName("testgroup1 vpc"),
		"testgroup description vpc",
	)
	c.Assert(err, IsNil)
	group := groupResp.SecurityGroup

	defer s.deleteGroups(c, []ec2.SecurityGroup{group})

	// Run a single instance with a new network interface.
	ips := []ec2.PrivateIP{
		{Address: "10.6.1.10", IsPrimary: true},
		{Address: "10.6.1.20", IsPrimary: false},
	}
	instResp, err := s.ec2.RunInstances(&ec2.RunInstances{
		MinCount:     1,
		ImageId:      imageId,
		InstanceType: "t1.micro",
		NetworkInterfaces: []ec2.RunNetworkInterface{{
			DeviceIndex:         0,
			SubnetId:            subId,
			PrivateIPs:          ips,
			SecurityGroupIds:    []string{group.Id},
			DeleteOnTermination: true,
		}},
	})
	c.Assert(err, IsNil)
	inst := &instResp.Instances[0]

	defer terminateInstances(c, s.ec2, []string{inst.InstanceId})

	// Now list the network interfaces and find ours.
	testAttempt := aws.AttemptStrategy{
		Total: 5 * time.Minute,
		Delay: 5 * time.Second,
	}
	f := ec2.NewFilter()
	f.Add("subnet-id", subId)
	var newNIC *ec2.NetworkInterface
	for a := testAttempt.Start(); a.Next(); {
		c.Logf("waiting for NIC to become available")
		listNICs, err := s.ec2.NetworkInterfaces(nil, f)
		if err != nil {
			c.Logf("retrying; NetworkInterfaces returned: %v", err)
			continue
		}
		for _, iface := range listNICs.Interfaces {
			c.Logf("found NIC %v", iface)
			if iface.Attachment.InstanceId == inst.InstanceId {
				c.Logf("instance %v new NIC appeared", inst.InstanceId)
				newNIC = &iface
				break
			}
		}
		if newNIC != nil {
			break
		}
	}
	if newNIC == nil {
		c.Fatalf("timeout while waiting for NIC to appear.")
	}
	c.Check(newNIC.Id, Matches, `^eni-[0-9a-f]+$`)
	c.Check(newNIC.SubnetId, Equals, subId)
	c.Check(newNIC.VPCId, Equals, vpcId)
	c.Check(newNIC.Status, Matches, `^(attaching|in-use)$`)
	c.Check(newNIC.PrivateIPAddress, Equals, ips[0].Address)
	c.Check(newNIC.PrivateIPs, DeepEquals, ips)
	c.Check(newNIC.Groups, HasLen, 1)
	c.Check(newNIC.Groups[0].Id, Equals, group.Id)
	c.Check(newNIC.Attachment.Status, Matches, `^(attaching|attached)$`)
	c.Check(newNIC.Attachment.DeviceIndex, Equals, 0)
	c.Check(newNIC.Attachment.DeleteOnTermination, Equals, true)
}
Esempio n. 11
0
func (s *AmazonServerSuite) TestAssignUnassignPrivateIPs(c *C) {
	vpcResp, err := s.ec2.CreateVPC("10.7.0.0/16", "")
	c.Assert(err, IsNil)
	vpcId := vpcResp.VPC.Id
	defer s.deleteVPCs(c, []string{vpcId})

	subResp := s.createSubnet(c, vpcId, "10.7.1.0/24", "")
	subId := subResp.Subnet.Id
	defer s.deleteSubnets(c, []string{subId})

	// Launch a m1.small instance, so we can later assign up to 4
	// private IPs.
	instList, err := s.ec2.RunInstances(&ec2.RunInstances{
		ImageId:      imageId,
		InstanceType: "m1.small",
		SubnetId:     subId,
	})
	c.Assert(err, IsNil)
	inst := instList.Instances[0]
	c.Assert(inst, NotNil)
	instId := inst.InstanceId
	defer terminateInstances(c, s.ec2, []string{instId})

	// We need to wait for the instance to change state to 'running',
	// so its automatically created network interface on the created
	// subnet will appear.
	testAttempt := aws.AttemptStrategy{
		Total: 5 * time.Minute,
		Delay: 5 * time.Second,
	}
	var newNIC *ec2.NetworkInterface
	f := ec2.NewFilter()
	f.Add("subnet-id", subId)
	for a := testAttempt.Start(); a.Next(); {
		resp, err := s.ec2.NetworkInterfaces(nil, f)
		if err != nil {
			c.Logf("NetworkInterfaces returned: %v; retrying...", err)
			continue
		}
		for _, iface := range resp.Interfaces {
			c.Logf("found NIC %v", iface)
			if iface.Attachment.InstanceId == instId {
				c.Logf("found instance %v NIC", instId)
				newNIC = &iface
				break
			}
		}
		if newNIC != nil {
			break
		}
	}
	if newNIC == nil {
		c.Fatalf("timeout while waiting for the NIC to appear")
	}

	c.Check(newNIC.PrivateIPAddress, Matches, `^10\.7\.1\.\d+$`)
	c.Check(newNIC.PrivateIPs, HasLen, 1)

	// Now let's try assigning some more private IPs.
	ips := []string{"10.7.1.25", "10.7.1.30"}
	_, err = s.ec2.AssignPrivateIPAddresses(newNIC.Id, ips, 0, false)
	c.Assert(err, IsNil)

	expectIPs := append([]string{newNIC.PrivateIPAddress}, ips...)
	s.waitForAddresses(c, newNIC.Id, expectIPs)

	// And finally, unassign them.
	_, err = s.ec2.UnassignPrivateIPAddresses(newNIC.Id, ips)
	c.Assert(err, IsNil)

	expectIPs = []string{newNIC.PrivateIPAddress}
	s.waitForAddresses(c, newNIC.Id, expectIPs)
}
Esempio n. 12
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func (S) TestAttemptNextHasNext(c *C) {
	a := aws.AttemptStrategy{}.Start()
	c.Assert(a.Next(), Equals, true)
	c.Assert(a.Next(), Equals, false)

	a = aws.AttemptStrategy{}.Start()
	c.Assert(a.Next(), Equals, true)
	c.Assert(a.HasNext(), Equals, false)
	c.Assert(a.Next(), Equals, false)

	a = aws.AttemptStrategy{Total: 2e8}.Start()
	c.Assert(a.Next(), Equals, true)
	c.Assert(a.HasNext(), Equals, true)
	time.Sleep(2e8)
	c.Assert(a.HasNext(), Equals, true)
	c.Assert(a.Next(), Equals, true)
	c.Assert(a.Next(), Equals, false)

	a = aws.AttemptStrategy{Total: 1e8, Min: 2}.Start()
	time.Sleep(1e8)
	c.Assert(a.Next(), Equals, true)
	c.Assert(a.HasNext(), Equals, true)
	c.Assert(a.Next(), Equals, true)
	c.Assert(a.HasNext(), Equals, false)
	c.Assert(a.Next(), Equals, false)
}