test(db): cover dbSource exception path in doClose()

Author: warku123

framework/src/test/java/org/tron/core/db/CheckPointV2StoreTest.java

@@ -68,6 +68,24 @@ public void testCloseReleasesAllResources() throws Exception {
     }
   }
 
+  @Test
+  public void testCloseWhenDbSourceThrows() throws Exception {
+    CheckPointV2Store store = new CheckPointV2Store("test-close-dbsource-throws");
+
+    Field dbSourceField = TronDatabase.class.getDeclaredField("dbSource");
+    dbSourceField.setAccessible(true);
+    DbSourceInter<byte[]> originalDbSource = (DbSourceInter<byte[]>) dbSourceField.get(store);
+    DbSourceInter<byte[]> mockDbSource = mock(DbSourceInter.class);
+    doThrow(new RuntimeException("simulated dbSource failure")).when(mockDbSource).closeDB();
+    dbSourceField.set(store, mockDbSource);
+
+    try {
+      store.close();
+    } finally {
+      originalDbSource.closeDB();
+    }
+  }
+
   @Test
   public void testCloseDbSourceWhenWriteOptionsThrows() throws Exception {
     CheckPointV2Store store = new CheckPointV2Store("test-close-exception");