cgroup2: io: add io.stats parsing test

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>

libcontainer/cgroups/fs2/io_test.go

@@ -0,0 +1,87 @@
+package fs2
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"reflect"
+	"sort"
+	"testing"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
+)
+
+const exampleIoStatData = `254:1 rbytes=6901432320 wbytes=14245535744 rios=263278 wios=248603 dbytes=0 dios=0
+254:0 rbytes=2702336 wbytes=0 rios=97 wios=0 dbytes=0 dios=0
+259:0 rbytes=6911345664 wbytes=14245536256 rios=264538 wios=244914 dbytes=530485248 dios=2`
+
+var exampleIoStatsParsed = cgroups.BlkioStats{
+	IoServiceBytesRecursive: []cgroups.BlkioStatEntry{
+		{Major: 254, Minor: 1, Value: 6901432320, Op: "Read"},
+		{Major: 254, Minor: 1, Value: 14245535744, Op: "Write"},
+		{Major: 254, Minor: 0, Value: 2702336, Op: "Read"},
+		{Major: 254, Minor: 0, Value: 0, Op: "Write"},
+		{Major: 259, Minor: 0, Value: 6911345664, Op: "Read"},
+		{Major: 259, Minor: 0, Value: 14245536256, Op: "Write"},
+	},
+	IoServicedRecursive: []cgroups.BlkioStatEntry{
+		{Major: 254, Minor: 1, Value: 263278, Op: "Read"},
+		{Major: 254, Minor: 1, Value: 248603, Op: "Write"},
+		{Major: 254, Minor: 0, Value: 97, Op: "Read"},
+		{Major: 254, Minor: 0, Value: 0, Op: "Write"},
+		{Major: 259, Minor: 0, Value: 264538, Op: "Read"},
+		{Major: 259, Minor: 0, Value: 244914, Op: "Write"},
+	},
+}
+
+func lessBlkioStatEntry(a, b cgroups.BlkioStatEntry) bool {
+	if a.Major != b.Major {
+		return a.Major < b.Major
+	}
+	if a.Minor != b.Minor {
+		return a.Minor < b.Minor
+	}
+	if a.Op != b.Op {
+		return a.Op < b.Op
+	}
+	return a.Value < b.Value
+}
+
+func sortBlkioStats(stats *cgroups.BlkioStats) {
+	for _, table := range []*[]cgroups.BlkioStatEntry{
+		&stats.IoServicedRecursive,
+		&stats.IoServiceBytesRecursive,
+	} {
+		sort.SliceStable(*table, func(i, j int) bool { return lessBlkioStatEntry((*table)[i], (*table)[j]) })
+	}
+}
+
+func TestStatIo(t *testing.T) {
+	// We're using a fake cgroupfs.
+	fscommon.TestMode = true
+
+	fakeCgroupDir, err := ioutil.TempDir("", "runc-stat-io-test.*")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(fakeCgroupDir)
+	statPath := filepath.Join(fakeCgroupDir, "io.stat")
+
+	if err := ioutil.WriteFile(statPath, []byte(exampleIoStatData), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	var gotStats cgroups.Stats
+	if err := statIo(fakeCgroupDir, &gotStats); err != nil {
+		t.Error(err)
+	}
+
+	// Sort the output since statIo uses a map internally.
+	sortBlkioStats(&gotStats.BlkioStats)
+	sortBlkioStats(&exampleIoStatsParsed)
+
+	if !reflect.DeepEqual(gotStats.BlkioStats, exampleIoStatsParsed) {
+		t.Errorf("parsed cgroupv2 io.stat doesn't match expected result: \ngot %#v\nexpected %#v\n", gotStats.BlkioStats, exampleIoStatsParsed)
+	}
+}