func TestTopologyWithSimpleCpuinfo(t *testing.T) {
	sysFs := &fakesysfs.FakeSysFs{}
	c := sysfs.CacheInfo{
		Size:  32 * 1024,
		Type:  "unified",
		Level: 1,
		Cpus:  1,
	}
	sysFs.SetCacheInfo(c)
	topology, numCores, err := getTopology(sysFs, "processor\t: 0\n")
	if err != nil {
		t.Errorf("Expected cpuinfo with no topology data to succeed.")
	}
	node := info.Node{Id: 0}
	core := info.Core{Id: 0}
	core.Threads = append(core.Threads, 0)
	cache := info.Cache{
		Size:  32 * 1024,
		Type:  "unified",
		Level: 1,
	}
	core.Caches = append(core.Caches, cache)
	node.Cores = append(node.Cores, core)
	// Copy over Memory from result. TODO(rjnagal): Use memory from fake.
	node.Memory = topology[0].Memory
	expected := []info.Node{node}
	if !reflect.DeepEqual(topology, expected) {
		t.Errorf("Expected topology %+v, got %+v", expected, topology)
	}
	if numCores != 1 {
		t.Errorf("Expected 1 core, found %d", numCores)
	}
}

func addNode(nodes *[]info.Node, id int) (int, error) {
	var idx int
	if id == -1 {
		// Some VMs don't fill topology data. Export single package.
		id = 0
	}

	ok, idx := findNode(*nodes, id)
	if !ok {
		// New node
		node := info.Node{Id: id}
		// Add per-node memory information.
		meminfo := fmt.Sprintf("/sys/devices/system/node/node%d/meminfo", id)
		out, err := ioutil.ReadFile(meminfo)
		// Ignore if per-node info is not available.
		if err == nil {
			m, err := parseCapacity(out, memoryCapacityRegexp)
			if err != nil {
				return -1, err
			}
			node.Memory = uint64(m)
		}
		*nodes = append(*nodes, node)
		idx = len(*nodes) - 1
	}
	return idx, nil
}

func TestTopology(t *testing.T) {
	testfile := "./testdata/cpuinfo"
	testcpuinfo, err := ioutil.ReadFile(testfile)
	if err != nil {
		t.Fatalf("unable to read input test file %s", testfile)
	}
	sysFs := &fakesysfs.FakeSysFs{}
	c := sysfs.CacheInfo{
		Size:  32 * 1024,
		Type:  "unified",
		Level: 1,
		Cpus:  2,
	}
	sysFs.SetCacheInfo(c)
	topology, numCores, err := getTopology(sysFs, string(testcpuinfo))
	if err != nil {
		t.Errorf("failed to get topology for sample cpuinfo %s", string(testcpuinfo))
	}

	if numCores != 12 {
		t.Errorf("Expected 12 cores, found %d", numCores)
	}
	expected_topology := []info.Node{}
	numNodes := 2
	numCoresPerNode := 3
	numThreads := 2
	cache := info.Cache{
		Size:  32 * 1024,
		Type:  "unified",
		Level: 1,
	}
	for i := 0; i < numNodes; i++ {
		node := info.Node{Id: i}
		// Copy over Memory from result. TODO(rjnagal): Use memory from fake.
		node.Memory = topology[i].Memory
		for j := 0; j < numCoresPerNode; j++ {
			core := info.Core{Id: i*numCoresPerNode + j}
			core.Caches = append(core.Caches, cache)
			for k := 0; k < numThreads; k++ {
				core.Threads = append(core.Threads, k*numCoresPerNode*numNodes+core.Id)
			}
			node.Cores = append(node.Cores, core)
		}
		expected_topology = append(expected_topology, node)
	}

	if !reflect.DeepEqual(topology, expected_topology) {
		t.Errorf("Expected topology %+v, got %+v", expected_topology, topology)
	}
}