libct/int: add/use needUserNS helper

Signed-off-by: Kir Kolyshkin <[email protected]>

Author: kolyshkin

libcontainer/integration/exec_test.go

@@ -3,7 +3,6 @@ package integration
 import (
 	"bytes"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"os"
 	"os/exec"
@@ -30,9 +29,7 @@ func TestExecPS(t *testing.T) {
 }
 
 func TestUsernsExecPS(t *testing.T) {
-	if _, err := os.Stat("/proc/self/ns/user"); os.IsNotExist(err) {
-		t.Skip("Test requires userns.")
-	}
+	needUserNS(t)
 	testExecPS(t, true)
 }
 
@@ -122,10 +119,7 @@ func TestRlimit(t *testing.T) {
 }
 
 func TestUsernsRlimit(t *testing.T) {
-	if _, err := os.Stat("/proc/self/ns/user"); os.IsNotExist(err) {
-		t.Skip("Test requires userns.")
-	}
-
+	needUserNS(t)
 	testRlimit(t, true)
 }
 
@@ -1515,9 +1509,7 @@ func TestInitJoinPID(t *testing.T) {
 }
 
 func TestInitJoinNetworkAndUser(t *testing.T) {
-	if _, err := os.Stat("/proc/self/ns/user"); os.IsNotExist(err) {
-		t.Skip("Test requires userns.")
-	}
+	needUserNS(t)
 	if testing.Short() {
 		return
 	}
@@ -1764,10 +1756,7 @@ next_fd:
 // Test that a container using user namespaces is able to bind mount a folder
 // that does not have permissions for group/others.
 func TestBindMountAndUser(t *testing.T) {
-	if _, err := os.Stat("/proc/self/ns/user"); errors.Is(err, os.ErrNotExist) {
-		t.Skip("userns is unsupported")
-	}
-
+	needUserNS(t)
 	if testing.Short() {
 		return
 	}

libcontainer/integration/execin_test.go

@@ -69,10 +69,7 @@ func TestExecIn(t *testing.T) {
 }
 
 func TestExecInUsernsRlimit(t *testing.T) {
-	if _, err := os.Stat("/proc/self/ns/user"); os.IsNotExist(err) {
-		t.Skip("Test requires userns.")
-	}
-
+	needUserNS(t)
 	testExecInRlimit(t, true)
 }
 
@@ -502,9 +499,7 @@ func TestExecInOomScoreAdj(t *testing.T) {
 }
 
 func TestExecInUserns(t *testing.T) {
-	if _, err := os.Stat("/proc/self/ns/user"); os.IsNotExist(err) {
-		t.Skip("Test requires userns.")
-	}
+	needUserNS(t)
 	if testing.Short() {
 		return
 	}

libcontainer/integration/utils_test.go

@@ -2,6 +2,7 @@ package integration
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"os"
 	"os/exec"
@@ -231,3 +232,10 @@ func runContainerOk(t testing.TB, config *configs.Config, args ...string) *stdBu
 func destroyContainer(container *libcontainer.Container) {
 	_ = container.Destroy()
 }
+
+func needUserNS(t testing.TB) {
+	t.Helper()
+	if _, err := os.Stat("/proc/self/ns/user"); errors.Is(err, os.ErrNotExist) {
+		t.Skip("Test requires userns.")
+	}
+}