Derive Arbitrary for Sealed<T> (#762)

* Derive arbitrary for Sealed<T>

* Manual impl Arbitrary for Sealed<T>

* Fix lint

crates/primitives/src/sealed.rs

@@ -8,6 +8,7 @@ use crate::B256;
 /// implement the [`Sealable`] trait to provide define their own hash.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Deref)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "arbitrary", derive(proptest_derive::Arbitrary))]
 pub struct Sealed<T> {
     /// The inner item
     #[deref]
@@ -62,6 +63,16 @@ impl<T> Sealed<T> {
     }
 }
 
+#[cfg(feature = "arbitrary")]
+impl<'a, T> arbitrary::Arbitrary<'a> for Sealed<T>
+where
+    T: for<'b> arbitrary::Arbitrary<'b> + Sealable,
+{
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        Ok(T::arbitrary(u)?.seal_slow())
+    }
+}
+
 /// Sealeable objects.
 pub trait Sealable: Sized {
     /// Calculate the seal hash, this may be slow.