1 files changed, 4 insertions, 0 deletions
diff --git a/src/ninep/tree.zig b/src/ninep/tree.zig
index 322728da..53d33731 100644
--- a/src/ninep/tree.zig
+++ b/src/ninep/tree.zig
@@ -1861,6 +1861,10 @@ test "no placement leaves a pane shorter than its tag and two rows; a full colum
     } else return error.NeverRefused;
     try testing.expectEqual(E.NOSPC, refused.errno());
     try testing.expect(std.mem.indexOf(u8, refused.reply.ename, "no space for a pane in that column") != null);
+    // The refused pane was never there: no serial spent on it.
+    const before = p.next_serial;
+    try testing.expectEqual(E.NOSPC, call(p, .{ .tag = 1, .op = .open, .node = new }).errno());
+    try testing.expectEqual(before, p.next_serial);
     p.sync();
     var count: usize = 0;
     for (p.panes) |slot| count += @intFromBool(slot != null);