Merge pull request #66850 from linyouchong/pr-0801-issue66809

Automatic merge from submit-queue (batch tested with PRs 66850, 66902, 66779, 66864, 66912). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Fix unit test failure: TestNsenterExistsFile

**What this PR does / why we need it**:
Fix unit test failure: TestNsenterExistsFile

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #66809 

**Special notes for your reviewer**:
NONE

**Release note**:
```release-note
NONE
```

pkg/util/mount/nsenter_mount_test.go

@@ -21,6 +21,7 @@ package mount
 import (
 	"io/ioutil"
 	"os"
+	"os/user"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -168,6 +169,12 @@ func newFakeNsenterMounter(tmpdir string, t *testing.T) (mounter *NsenterMounter
 }
 
 func TestNsenterExistsFile(t *testing.T) {
+	user, err := user.Current()
+	if err != nil {
+		t.Error(err)
+	}
+	isRoot := user.Username == "root"
+
 	tests := []struct {
 		name           string
 		prepare        func(base, rootfs string) (string, error)
@@ -227,8 +234,8 @@ func TestNsenterExistsFile(t *testing.T) {
 
 				return path, nil
 			},
-			expectedOutput: false,
+			expectedOutput: isRoot,  // ExistsPath success when running as root
-			expectError:    true,
+			expectError:    !isRoot, // ExistsPath must fail when running as not-root
 		},
 		{
 			name: "relative symlink to existing file",