diff --git a/MyPassCore/Tests/MyPassCoreTests/GroupSelectionTests.swift b/MyPassCore/Tests/MyPassCoreTests/GroupSelectionTests.swift
index b5c5a84..ded5ef2 100644
--- a/MyPassCore/Tests/MyPassCoreTests/GroupSelectionTests.swift
+++ b/MyPassCore/Tests/MyPassCoreTests/GroupSelectionTests.swift
@@ -39,4 +39,19 @@ final class GroupSelectionTests: XCTestCase {
         let result = GroupSelection.toggling(work.id, in: root, current: [personal.id])
         XCTAssertEqual(result, [personal.id, work.id, email.id])
     }
+
+    func test_subtreeIds_groupNotFound_returnsEmptySet() {
+        let (root, _, _, _) = makeSampleTree()
+        let nonExistentId = UUID()
+        let ids = GroupSelection.subtreeIds(of: nonExistentId, in: root)
+        XCTAssertEqual(ids, [])
+    }
+
+    func test_toggling_groupNotFound_returnsCurrentUnchanged() {
+        let (root, _, _, personal) = makeSampleTree()
+        let nonExistentId = UUID()
+        let current: Set<UUID> = [personal.id]
+        let result = GroupSelection.toggling(nonExistentId, in: root, current: current)
+        XCTAssertEqual(result, current)
+    }
 }