1 files changed, 37 insertions, 0 deletions
diff --git a/src/transport/mod.rs b/src/transport/mod.rs
index c3db962..35e3499 100644
--- a/src/transport/mod.rs
+++ b/src/transport/mod.rs
@@ -328,3 +328,40 @@ pub trait Transport: Send + Sync {
     /// Asynchronously monitors for fatal network client or sub-process failures.
     async fn wait_for_exit(&self) -> std::io::Result<std::process::ExitStatus>;
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::testrand::for_seeds;
+
+    /// Two summaries are equal exactly when the heads are, in any order, whichever form
+    /// (listed or digest) each took.
+    #[test]
+    fn heads_summary_equality_is_set_equality() {
+        for_seeds(300, |rng| {
+            let n = rng.between(0, 2 * MAX_LISTED_HEADS + 2);
+            let heads: Vec<ChangeHash> = (0..n).map(|_| ChangeHash(rng.bytes32())).collect();
+            let summary = HeadsSummary::of(heads.clone());
+            assert_eq!(summary.heads().is_some(), n <= MAX_LISTED_HEADS);
+
+            let mut shuffled = heads.clone();
+            rng.shuffle(&mut shuffled);
+            assert_eq!(summary, HeadsSummary::of(shuffled));
+            assert_eq!(summary, HeadsSummary::Digest(summary.digest()));
+
+            let mut other = heads.clone();
+            match rng.below(3) {
+                1 if !other.is_empty() => {
+                    let i = rng.below(other.len());
+                    other.remove(i);
+                }
+                2 if !other.is_empty() => {
+                    let i = rng.below(other.len());
+                    other[i] = ChangeHash(rng.bytes32());
+                }
+                _ => other.push(ChangeHash(rng.bytes32())),
+            }
+            assert_ne!(summary, HeadsSummary::of(other));
+        });
+    }
+}