Add iterator fail-fast tests for LinkedTreeMap.clear() (#2992)

lmj798 · web-flow · commit b7d595491888 · 2026-03-10T08:12:15.000-07:00
* Add boundary tests for JsonTreeWriter.endArray() error handling

* Add comprehensive boundary tests for LinkedTreeMap.clear() method

* Update JsonTreeWriterTest.java

* Remove redundant clear map tests from LinkedTreeMapTest

Removed multiple test cases for clearing LinkedTreeMap, including tests for single and multiple entries, null values, and various scenarios.

* Remove blank line in LinkedTreeMapTest

Removed unnecessary blank line in LinkedTreeMapTest.
diff --git a/gson/src/test/java/com/google/gson/internal/LinkedTreeMapTest.java b/gson/src/test/java/com/google/gson/internal/LinkedTreeMapTest.java
@@ -26,6 +26,7 @@
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.util.Collections;
+import java.util.ConcurrentModificationException;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -219,4 +220,34 @@ public void testJavaSerialization() throws IOException, ClassNotFoundException {
     Map<String, Integer> deserialized = (Map<String, Integer>) objIn.readObject();
     assertThat(deserialized).isEqualTo(Collections.singletonMap("a", 1));
   }
+
+  @Test
+  public void testClearInvalidatesExistingIterator() {
+    LinkedTreeMap<String, String> map = new LinkedTreeMap<>();
+    map.put("key1", "value1");
+    map.put("key2", "value2");
+    map.put("key3", "value3");
+
+    Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();
+    assertThat(iterator.hasNext()).isTrue();
+
+    map.clear();
+
+    assertThrows(ConcurrentModificationException.class, iterator::next);
+  }
+
+  @Test
+  public void testClearInvalidatesExistingKeySetIterator() {
+    LinkedTreeMap<String, String> map = new LinkedTreeMap<>();
+    map.put("key1", "value1");
+    map.put("key2", "value2");
+    map.put("key3", "value3");
+
+    Iterator<String> iterator = map.keySet().iterator();
+    assertThat(iterator.hasNext()).isTrue();
+
+    map.clear();
+
+    assertThrows(ConcurrentModificationException.class, iterator::next);
+  }
 }
