diff --git a/container/initdev.go b/container/initdev.go
index 827df9e..c06cf22 100644
--- a/container/initdev.go
+++ b/container/initdev.go
@@ -126,8 +126,14 @@ func (d *MountDevOp) apply(state *setupState) error {
 		fmt.Sprintf("cannot remount %q:", target))
 }
 
-func (d *MountDevOp) Is(op Op) bool { vd, ok := op.(*MountDevOp); return ok && *d == *vd }
-func (*MountDevOp) prefix() string  { return "mounting" }
+func (d *MountDevOp) Is(op Op) bool {
+	vd, ok := op.(*MountDevOp)
+	return ok && ((d == nil && vd == nil) || (d != nil && vd != nil &&
+		d.Target != nil && vd.Target != nil &&
+		d.Target.String() == vd.Target.String() &&
+		d.Mqueue == vd.Mqueue && d.Write == vd.Write))
+}
+func (*MountDevOp) prefix() string { return "mounting" }
 func (d *MountDevOp) String() string {
 	if d.Mqueue {
 		return fmt.Sprintf("dev on %q with mqueue", d.Target)
diff --git a/container/initdev_test.go b/container/initdev_test.go
new file mode 100644
index 0000000..3df56d5
--- /dev/null
+++ b/container/initdev_test.go
@@ -0,0 +1,61 @@
+package container
+
+import "testing"
+
+func TestMountDevOp(t *testing.T) {
+	checkOpsBuilder(t, []opsBuilderTestCase{
+		{"dev", new(Ops).Dev(MustAbs("/dev/"), true), Ops{
+			&MountDevOp{
+				Target: MustAbs("/dev/"),
+				Mqueue: true,
+			},
+		}},
+
+		{"dev writable", new(Ops).DevWritable(MustAbs("/.hakurei/dev/"), false), Ops{
+			&MountDevOp{
+				Target: MustAbs("/.hakurei/dev/"),
+				Write:  true,
+			},
+		}},
+	})
+
+	checkOpIs(t, []opIsTestCase{
+		{"zero", new(MountDevOp), new(MountDevOp), false},
+
+		{"equals", &MountDevOp{
+			Target: MustAbs("/dev/"),
+			Mqueue: true,
+		}, &MountDevOp{
+			Target: MustAbs("/dev/"),
+			Mqueue: true,
+		}, true},
+
+		{"differs", &MountDevOp{
+			Target: MustAbs("/dev/"),
+			Mqueue: true,
+		}, &MountDevOp{
+			Target: MustAbs("/dev/"),
+			Mqueue: true,
+			Write:  true,
+		}, false},
+
+		{"differs path", &MountDevOp{
+			Target: MustAbs("/"),
+			Mqueue: true,
+		}, &MountDevOp{
+			Target: MustAbs("/dev/"),
+			Mqueue: true,
+		}, false},
+	})
+
+	checkOpMeta(t, []opMetaTestCase{
+		{"mqueue", &MountDevOp{
+			Target: MustAbs("/dev/"),
+			Mqueue: true,
+		}, "mounting", `dev on "/dev/" with mqueue`},
+
+		{"dev", &MountDevOp{
+			Target: MustAbs("/dev/"),
+		}, "mounting", `dev on "/dev/"`},
+	})
+}