diff --git a/fuzz/fuzz_targets/mpu_crdt.rs b/fuzz/fuzz_targets/mpu_crdt.rs
index 82d6b613..86eb9900 100644
--- a/fuzz/fuzz_targets/mpu_crdt.rs
+++ b/fuzz/fuzz_targets/mpu_crdt.rs
@@ -1,7 +1,7 @@
 #![no_main]
 
+use garage_fuzz::check_crdt_laws;
 use garage_model::s3::mpu_table::{MpuPart, MpuPartKey, MultipartUpload};
-use garage_table::crdt::Crdt;
 use libfuzzer_sys::fuzz_target;
 
 /// Build a MultipartUpload from an arbitrary deleted flag and parts list, using a fixed
@@ -27,67 +27,11 @@ fn make_mpu(deleted: bool, parts: Vec<(MpuPartKey, MpuPart)>) -> MultipartUpload
 	mpu
 }
 
-fn crdt_state(mpu: &MultipartUpload) -> (bool, &[(MpuPartKey, MpuPart)]) {
-	(mpu.deleted.get(), mpu.parts.items())
-}
-
 fuzz_target!(|inputs: (
 	(bool, Vec<(MpuPartKey, MpuPart)>),
 	(bool, Vec<(MpuPartKey, MpuPart)>),
 	(bool, Vec<(MpuPartKey, MpuPart)>)
 )| {
 	let ((d1, p1), (d2, p2), (d3, p3)) = inputs;
-	let a = make_mpu(d1, p1);
-	let b = make_mpu(d2, p2);
-	let c = make_mpu(d3, p3);
-
-	// Idempotency: merge(a, a) == a
-	{
-		let mut a2 = a.clone();
-		a2.merge(&a.clone());
-		assert_eq!(
-			crdt_state(&a2),
-			crdt_state(&a),
-			"merge is not idempotent: {a2:#?} != {a:#?}"
-		);
-	}
-
-	// Commutativity: crdt_state(merge(a, b)) == crdt_state(merge(b, a))
-	let ab = {
-		let mut t = a.clone();
-		t.merge(&b);
-		t
-	};
-	let ba = {
-		let mut t = b.clone();
-		t.merge(&a);
-		t
-	};
-	assert_eq!(
-		crdt_state(&ab),
-		crdt_state(&ba),
-		"merge is not commutative: {ab:#?} != {ba:#?}"
-	);
-
-	// Associativity: crdt_state(merge(merge(a, b), c)) == crdt_state(merge(a, merge(b, c)))
-	let ab_c = {
-		let mut t = ab.clone();
-		t.merge(&c);
-		t
-	};
-	let bc = {
-		let mut t = b.clone();
-		t.merge(&c);
-		t
-	};
-	let a_bc = {
-		let mut t = a.clone();
-		t.merge(&bc);
-		t
-	};
-	assert_eq!(
-		crdt_state(&ab_c),
-		crdt_state(&a_bc),
-		"merge is not associative: {ab_c:#?} != {a_bc:#?}"
-	);
+	check_crdt_laws(make_mpu(d1, p1), make_mpu(d2, p2), make_mpu(d3, p3));
 });
diff --git a/fuzz/fuzz_targets/version_crdt.rs b/fuzz/fuzz_targets/version_crdt.rs
index 4be47666..cb0649bc 100644
--- a/fuzz/fuzz_targets/version_crdt.rs
+++ b/fuzz/fuzz_targets/version_crdt.rs
@@ -1,7 +1,7 @@
 #![no_main]
 
+use garage_fuzz::check_crdt_laws;
 use garage_model::s3::version_table::{Version, VersionBacklink, VersionBlock, VersionBlockKey};
-use garage_table::crdt::Crdt;
 use libfuzzer_sys::fuzz_target;
 
 /// Build a Version from an arbitrary deleted flag and block list, using a fixed uuid/backlink
@@ -28,67 +28,15 @@ fn make_version(deleted: bool, mut blocks: Vec<(VersionBlockKey, VersionBlock)>)
 	v
 }
 
-fn crdt_state(v: &Version) -> (bool, &[(VersionBlockKey, VersionBlock)]) {
-	(v.deleted.get(), v.blocks.items())
-}
-
 fuzz_target!(|inputs: (
 	(bool, Vec<(VersionBlockKey, VersionBlock)>),
 	(bool, Vec<(VersionBlockKey, VersionBlock)>),
 	(bool, Vec<(VersionBlockKey, VersionBlock)>)
 )| {
 	let ((d1, b1), (d2, b2), (d3, b3)) = inputs;
-	let a = make_version(d1, b1);
-	let b = make_version(d2, b2);
-	let c = make_version(d3, b3);
-
-	// Idempotency: merge(a, a) == a
-	{
-		let mut a2 = a.clone();
-		a2.merge(&a.clone());
-		assert_eq!(
-			crdt_state(&a2),
-			crdt_state(&a),
-			"merge is not idempotent: {a2:#?} != {a:#?}"
-		);
-	}
-
-	// Commutativity: crdt_state(merge(a, b)) == crdt_state(merge(b, a))
-	let ab = {
-		let mut t = a.clone();
-		t.merge(&b);
-		t
-	};
-	let ba = {
-		let mut t = b.clone();
-		t.merge(&a);
-		t
-	};
-	assert_eq!(
-		crdt_state(&ab),
-		crdt_state(&ba),
-		"merge is not commutative: {ab:#?} != {ba:#?}"
-	);
-
-	// Associativity: crdt_state(merge(merge(a, b), c)) == crdt_state(merge(a, merge(b, c)))
-	let ab_c = {
-		let mut t = ab.clone();
-		t.merge(&c);
-		t
-	};
-	let bc = {
-		let mut t = b.clone();
-		t.merge(&c);
-		t
-	};
-	let a_bc = {
-		let mut t = a.clone();
-		t.merge(&bc);
-		t
-	};
-	assert_eq!(
-		crdt_state(&ab_c),
-		crdt_state(&a_bc),
-		"merge is not associative: {ab_c:#?} != {a_bc:#?}"
+	check_crdt_laws(
+		make_version(d1, b1),
+		make_version(d2, b2),
+		make_version(d3, b3),
 	);
 });
diff --git a/fuzz/src/lib.rs b/fuzz/src/lib.rs
new file mode 100644
index 00000000..288ccced
--- /dev/null
+++ b/fuzz/src/lib.rs
@@ -0,0 +1,56 @@
+use garage_table::crdt::Crdt;
+use std::fmt::Debug;
+
+pub fn check_crdt_laws<T>(a: T, b: T, c: T)
+where
+	T: Crdt + PartialEq + Clone + Debug,
+{
+	// Idempotency: merge(a, a) == a
+	{
+		let mut a2 = a.clone();
+		a2.merge(&a);
+		assert_eq!(a2, a, "merge is not idempotent: {a2:#?} != {a:#?}");
+	}
+
+	// Commutativity: merge(a, b) == merge(b, a)
+	let ab = {
+		let mut t = a.clone();
+		t.merge(&b);
+		t
+	};
+	let ba = {
+		let mut t = b.clone();
+		t.merge(&a);
+		t
+	};
+	assert_eq!(ab, ba, "merge is not commutative: {ab:#?} != {ba:#?}");
+
+	// LX's corrolary: merge(merge(a,b),b) = merge(a,b)
+	let ab_b = {
+		let mut t = ab.clone();
+		t.merge(&b);
+		t
+	};
+	assert_eq!(ab, ab_b);
+
+	// Associativity: merge(merge(a, b), c) == merge(a, merge(b, c))
+	let ab_c = {
+		let mut t = ab;
+		t.merge(&c);
+		t
+	};
+	let bc = {
+		let mut t = b;
+		t.merge(&c);
+		t
+	};
+	let a_bc = {
+		let mut t = a;
+		t.merge(&bc);
+		t
+	};
+	assert_eq!(
+		ab_c, a_bc,
+		"merge is not associative: {ab_c:#?} != {a_bc:#?}"
+	);
+}