Move unix specific logic into _unix.go

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/helpers_unix_test.go

@@ -0,0 +1,58 @@
+// +build !windows
+
+/*
+Copyright The containerd Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package server
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetCgroupsPath(t *testing.T) {
+	testID := "test-id"
+	for desc, test := range map[string]struct {
+		cgroupsParent string
+		expected      string
+	}{
+		"should support regular cgroup path": {
+			cgroupsParent: "/a/b",
+			expected:      "/a/b/test-id",
+		},
+		"should support systemd cgroup path": {
+			cgroupsParent: "/a.slice/b.slice",
+			expected:      "b.slice:cri-containerd:test-id",
+		},
+		"should support tailing slash for regular cgroup path": {
+			cgroupsParent: "/a/b/",
+			expected:      "/a/b/test-id",
+		},
+		"should support tailing slash for systemd cgroup path": {
+			cgroupsParent: "/a.slice/b.slice/",
+			expected:      "b.slice:cri-containerd:test-id",
+		},
+		"should treat root cgroup as regular cgroup path": {
+			cgroupsParent: "/",
+			expected:      "/test-id",
+		},
+	} {
+		t.Logf("TestCase %q", desc)
+		got := getCgroupsPath(test.cgroupsParent, testID)
+		assert.Equal(t, test.expected, got)
+	}
+}