validator: actually test success

Previously we only tested failures, which causes us to miss issues where
setting sysctls would *always* fail.

Signed-off-by: Aleksa Sarai <asarai@suse.de>

libcontainer/configs/validate/validator_test.go

@@ -202,6 +202,35 @@ func TestValidateSysctl(t *testing.T) {
 	}
 }
 
+func TestValidateValidSysctl(t *testing.T) {
+	sysctl := map[string]string{
+		"fs.mqueue.ctl": "ctl",
+		"net.ctl":       "ctl",
+		"kernel.msgmax": "ctl",
+	}
+
+	for k, v := range sysctl {
+		config := &configs.Config{
+			Rootfs: "/var",
+			Sysctl: map[string]string{k: v},
+			Namespaces: []configs.Namespace{
+				{
+					Type: configs.NEWNET,
+				},
+				{
+					Type: configs.NEWIPC,
+				},
+			},
+		}
+
+		validator := validate.New()
+		err := validator.Validate(config)
+		if err != nil {
+			t.Errorf("Expected error to not occur with {%s=%s} but got: %q", k, v, err)
+		}
+	}
+}
+
 func TestValidateSysctlWithSameNs(t *testing.T) {
 	config := &configs.Config{
 		Rootfs: "/var",