Add cgroup manage for mocking of package resources

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

linux_container_test.go

@@ -0,0 +1,68 @@
+// +build linux
+
+package libcontainer
+
+import (
+	"testing"
+
+	"github.com/docker/libcontainer/cgroups"
+)
+
+type mockCgroupManager struct {
+	pids  []int
+	stats *cgroups.Stats
+}
+
+func (m *mockCgroupManager) GetPids(config *cgroups.Cgroup) ([]int, error) {
+	return m.pids, nil
+}
+
+func (m *mockCgroupManager) GetStats(config *cgroups.Cgroup) (*cgroups.Stats, error) {
+	return m.stats, nil
+}
+
+func TestGetContainerPids(t *testing.T) {
+	container := &linuxContainer{
+		id:            "myid",
+		config:        &Config{},
+		cgroupManager: &mockCgroupManager{pids: []int{1, 2, 3}},
+	}
+
+	pids, err := container.Processes()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i, expected := range []int{1, 2, 3} {
+		if pids[i] != expected {
+			t.Fatalf("expected pid %d but received %d", expected, pids[i])
+		}
+	}
+}
+
+func TestGetContainerStats(t *testing.T) {
+	container := &linuxContainer{
+		id:     "myid",
+		config: &Config{},
+		cgroupManager: &mockCgroupManager{
+			pids: []int{1, 2, 3},
+			stats: &cgroups.Stats{
+				MemoryStats: cgroups.MemoryStats{
+					Usage: 1024,
+				},
+			},
+		},
+		state: &State{},
+	}
+
+	stats, err := container.Stats()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stats.CgroupStats == nil {
+		t.Fatal("cgroup stats are nil")
+	}
+	if stats.CgroupStats.MemoryStats.Usage != 1024 {
+		t.Fatalf("expected memory usage 1024 but recevied %d", stats.CgroupStats.MemoryStats.Usage)
+	}
+}