diff --git a/container/container.go b/container/container.go
index 8001673..ecfb94c 100644
--- a/container/container.go
+++ b/container/container.go
@@ -17,6 +17,12 @@ import (
 	"hakurei.app/container/seccomp"
 )
 
+const (
+	// Nonexistent is a path that cannot exist.
+	// /proc is chosen because a system with covered /proc is unsupported by this package.
+	Nonexistent = "/proc/nonexistent"
+)
+
 type (
 	// Container represents a container environment being prepared or run.
 	// None of [Container] methods are safe for concurrent use.
diff --git a/container/seccomp/libseccomp_test.go b/container/seccomp/libseccomp_test.go
index 8443ade..1ae3f76 100644
--- a/container/seccomp/libseccomp_test.go
+++ b/container/seccomp/libseccomp_test.go
@@ -79,7 +79,7 @@ func TestExport(t *testing.T) {
 
 func BenchmarkExport(b *testing.B) {
 	buf := make([]byte, 8)
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		e := New(
 			Preset(PresetExt|PresetDenyNS|PresetDenyTTY|PresetDenyDevel|PresetLinux32,
 				AllowMultiarch|AllowCAN|AllowBluetooth),
diff --git a/helper/cmd_test.go b/helper/cmd_test.go
index 00342e6..64ac643 100644
--- a/helper/cmd_test.go
+++ b/helper/cmd_test.go
@@ -8,12 +8,13 @@ import (
 	"os/exec"
 	"testing"
 
+	"hakurei.app/container"
 	"hakurei.app/helper"
 )
 
 func TestCmd(t *testing.T) {
 	t.Run("start non-existent helper path", func(t *testing.T) {
-		h := helper.NewDirect(t.Context(), "/proc/nonexistent", argsWt, false, argF, nil, nil)
+		h := helper.NewDirect(t.Context(), container.Nonexistent, argsWt, false, argF, nil, nil)
 
 		if err := h.Start(); !errors.Is(err, os.ErrNotExist) {
 			t.Errorf("Start: error = %v, wantErr %v",
diff --git a/helper/container_test.go b/helper/container_test.go
index a65e87f..71c25bd 100644
--- a/helper/container_test.go
+++ b/helper/container_test.go
@@ -15,7 +15,7 @@ import (
 
 func TestContainer(t *testing.T) {
 	t.Run("start empty container", func(t *testing.T) {
-		h := helper.New(t.Context(), "/nonexistent", argsWt, false, argF, nil, nil)
+		h := helper.New(t.Context(), container.Nonexistent, argsWt, false, argF, nil, nil)
 
 		wantErr := "sandbox: starting an empty container"
 		if err := h.Start(); err == nil || err.Error() != wantErr {
diff --git a/system/acl_test.go b/system/acl_test.go
index a66207e..886a62e 100644
--- a/system/acl_test.go
+++ b/system/acl_test.go
@@ -3,6 +3,7 @@ package system
 import (
 	"testing"
 
+	"hakurei.app/container"
 	"hakurei.app/system/acl"
 )
 
@@ -52,19 +53,19 @@ func TestACLString(t *testing.T) {
 		et    Enablement
 		perms []acl.Perm
 	}{
-		{`--- type: process path: "/nonexistent"`, Process, []acl.Perm{}},
-		{`r-- type: user path: "/nonexistent"`, User, []acl.Perm{acl.Read}},
-		{`-w- type: wayland path: "/nonexistent"`, EWayland, []acl.Perm{acl.Write}},
-		{`--x type: x11 path: "/nonexistent"`, EX11, []acl.Perm{acl.Execute}},
-		{`rw- type: dbus path: "/nonexistent"`, EDBus, []acl.Perm{acl.Read, acl.Write}},
-		{`r-x type: pulseaudio path: "/nonexistent"`, EPulse, []acl.Perm{acl.Read, acl.Execute}},
-		{`rwx type: user path: "/nonexistent"`, User, []acl.Perm{acl.Read, acl.Write, acl.Execute}},
-		{`rwx type: process path: "/nonexistent"`, Process, []acl.Perm{acl.Read, acl.Write, acl.Write, acl.Execute}},
+		{`--- type: process path: "/proc/nonexistent"`, Process, []acl.Perm{}},
+		{`r-- type: user path: "/proc/nonexistent"`, User, []acl.Perm{acl.Read}},
+		{`-w- type: wayland path: "/proc/nonexistent"`, EWayland, []acl.Perm{acl.Write}},
+		{`--x type: x11 path: "/proc/nonexistent"`, EX11, []acl.Perm{acl.Execute}},
+		{`rw- type: dbus path: "/proc/nonexistent"`, EDBus, []acl.Perm{acl.Read, acl.Write}},
+		{`r-x type: pulseaudio path: "/proc/nonexistent"`, EPulse, []acl.Perm{acl.Read, acl.Execute}},
+		{`rwx type: user path: "/proc/nonexistent"`, User, []acl.Perm{acl.Read, acl.Write, acl.Execute}},
+		{`rwx type: process path: "/proc/nonexistent"`, Process, []acl.Perm{acl.Read, acl.Write, acl.Write, acl.Execute}},
 	}
 
 	for _, tc := range testCases {
 		t.Run(tc.want, func(t *testing.T) {
-			a := &ACL{et: tc.et, perms: tc.perms, path: "/nonexistent"}
+			a := &ACL{et: tc.et, perms: tc.perms, path: container.Nonexistent}
 			if got := a.String(); got != tc.want {
 				t.Errorf("String() = %v, want %v",
 					got, tc.want)
diff --git a/system/mkdir_test.go b/system/mkdir_test.go
index 4b00bb3..706b3d1 100644
--- a/system/mkdir_test.go
+++ b/system/mkdir_test.go
@@ -3,6 +3,8 @@ package system
 import (
 	"os"
 	"testing"
+
+	"hakurei.app/container"
 )
 
 func TestEnsure(t *testing.T) {
@@ -60,11 +62,11 @@ func TestMkdirString(t *testing.T) {
 		t.Run(tc.want, func(t *testing.T) {
 			m := &Mkdir{
 				et:        tc.et,
-				path:      "/nonexistent",
+				path:      container.Nonexistent,
 				perm:      0701,
 				ephemeral: tc.ephemeral,
 			}
-			want := "mode: " + os.FileMode(0701).String() + " type: " + tc.want + " path: \"/nonexistent\""
+			want := "mode: " + os.FileMode(0701).String() + " type: " + tc.want + ` path: "/proc/nonexistent"`
 			if got := m.String(); got != want {
 				t.Errorf("String() = %v, want %v", got, want)
 			}