add save-after-rollback test

1 files changed, 34 insertions, 0 deletions

diff --git a/src/document/replica.rs b/src/document/replica.rs
index 20c02e5..27c81ad 100644
--- a/src/document/replica.rs
+++ b/src/document/replica.rs
@@ -225,6 +225,40 @@ mod tests {
         assert_eq!(local.relation_to(&epoch(3, 2)), EpochRelation::Diverged);
     }
 
+    /// A rolled-back write leaves its writer unused in the document; saving must not
+    /// trip over it (Automerge refuses to save a document with unused writers).
+    #[test]
+    fn saves_after_a_rolled_back_write() {
+        use crate::clock::UnixMillis;
+        use crate::document::store;
+        use serde_json::json;
+
+        let path = vec!["a".to_owned()];
+        let mut replica = Replica::new(Epoch::GENESIS, Document::new());
+
+        let refused: Result<(), &str> = replica.transact(UnixMillis(1), |doc| {
+            store::write_path(doc, &path, &json!(1)).unwrap();
+            Err("refused")
+        });
+        assert!(refused.is_err());
+        let loaded = super::super::load(&super::super::save(&replica.doc)).unwrap();
+        assert!(loaded.get_heads().is_empty());
+        assert_eq!(store::read_path(&loaded, &path).unwrap(), None);
+
+        // The same writer commits afterwards, and that saves too.
+        replica
+            .transact(UnixMillis(2), |doc| {
+                store::write_path(doc, &path, &json!(2))
+            })
+            .unwrap();
+        replica.refresh_heads();
+        let loaded = super::super::load(&super::super::save(&replica.doc)).unwrap();
+        let mut heads = loaded.get_heads();
+        heads.sort_unstable();
+        assert_eq!(heads, replica.heads());
+        assert_eq!(store::read_path(&loaded, &path).unwrap(), Some(json!(2)));
+    }
+
     #[test]
     fn display() {
         assert_eq!(Epoch::GENESIS.to_string(), "0:genesis");