From 4bd821d627689c9dc8bad3b1e4d45bcadf70c6ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E7=82=8E=E6=B3=BC?= <drdr.xp@gmail.com>
Date: Tue, 23 Jul 2024 20:12:35 +0800
Subject: [PATCH] Chore: add test to ensure change_membership(.., retain=false)
 wont remove existing learners

---
 openraft/src/membership/membership_test.rs | 25 ++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/openraft/src/membership/membership_test.rs b/openraft/src/membership/membership_test.rs
index 47590bc8d..32fd1b6f6 100644
--- a/openraft/src/membership/membership_test.rs
+++ b/openraft/src/membership/membership_test.rs
@@ -293,3 +293,28 @@ fn test_membership_next_coherent_with_nodes() -> anyhow::Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn test_membership_next_coherent_retain_false_keeps_existing_learners() -> anyhow::Result<()> {
+    let node = |s: u64| TestNode {
+        addr: s.to_string(),
+        data: Default::default(),
+    };
+
+    let c1 = || btreeset! {1};
+    let c2 = || btreeset! {2};
+
+    let initial = Membership::<UTConfig<TestNode>>::new_unchecked(
+        vec![c1(), c2()],
+        btreemap! {1=>node(1), 2=>node(2), 3=>node(3)},
+    );
+
+    let res = initial.next_coherent(btreeset! {2}, false);
+    assert_eq!(&vec![btreeset! {2}], res.get_joint_config());
+    assert_eq!(
+        btreemap! {2=>node(2), 3=>node(3)},
+        res.nodes().map(|(nid, n)| (*nid, n.clone())).collect::<BTreeMap<_, _>>()
+    );
+
+    Ok(())
+}