From d703874f8723ceec8c2400abc60f73b144aa7560 Mon Sep 17 00:00:00 2001
From: Stephen Waits <1+swaits@noreply.git.swaits.com>
Date: Sun, 11 Oct 2026 02:25:59 +0000
Subject: [PATCH] asset slice + testing initiative: fixed assets,
 property/mutation/fuzz testing, docs

---
 fuzz/fuzz_targets/fuzz_journal_line.rs | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 fuzz/fuzz_targets/fuzz_journal_line.rs

diff --git a/fuzz/fuzz_targets/fuzz_journal_line.rs b/fuzz/fuzz_targets/fuzz_journal_line.rs
new file mode 100644
index 0000000..5c0b10f
--- /dev/null
+++ b/fuzz/fuzz_targets/fuzz_journal_line.rs
@@ -0,0 +1,24 @@
+// Fuzz target: journal line parsing must never panic, and the canonical
+// form must be a fixed point: parse(canonical(x)) re-serializes to the
+// same canonical bytes. Staged here; `cargo fuzz init` wires it up.
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use ledger_store::JournalLine;
+
+fuzz_target!(|data: &[u8]| {
+    // Garbage must return Err, never panic.
+    if let Ok(line) = serde_json::from_slice::<JournalLine>(data) {
+        let canon = line.to_canonical();
+        let line2: JournalLine =
+            serde_json::from_str(&canon).expect("canonical form must re-parse");
+        assert_eq!(
+            line2.to_canonical(),
+            canon,
+            "canonical form is not a fixed point"
+        );
+        // Sequence numbers survive the round trip.
+        assert_eq!(line.seq, line2.seq);
+        assert_eq!(line.line_type, line2.line_type);
+    }
+});