From 8810c4faf1491142f360d0a510c6e9f2607e8454 Mon Sep 17 00:00:00 2001
From: Seung Hyun Kim <skim449@illinois.edu>
Date: Sun, 30 Jun 2024 21:04:52 -0500
Subject: [PATCH] fix: first callback execution

---
 elastica/modules/callbacks.py        |  3 +++
 tests/test_modules/test_callbacks.py | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/elastica/modules/callbacks.py b/elastica/modules/callbacks.py
index 9d886926..4028b94a 100644
--- a/elastica/modules/callbacks.py
+++ b/elastica/modules/callbacks.py
@@ -74,6 +74,9 @@ def _finalize_callback(self: SystemCollectionProtocol) -> None:
         self._callback_list.clear()
         del self._callback_list
 
+        # First callback execution
+        self.apply_callbacks(time=np.float64(0.0), current_step=0)
+
 
 class _CallBack:
     """
diff --git a/tests/test_modules/test_callbacks.py b/tests/test_modules/test_callbacks.py
index d5830229..da786b75 100644
--- a/tests/test_modules/test_callbacks.py
+++ b/tests/test_modules/test_callbacks.py
@@ -184,3 +184,15 @@ def test_callback_finalize_sorted(self, load_rod_with_callbacks):
         for x, _ in scwc._callback_list:
             assert num < x
             num = x
+
+    def test_first_call_callback_during_finalize(self, mocker, load_rod_with_callbacks):
+        scwc, callback_cls = load_rod_with_callbacks
+        callback_features = [d for d in scwc._callback_list]
+
+        spy = mocker.spy(scwc, "apply_callbacks")
+        scwc._finalize_callback()
+
+        assert spy.call_count == 1
+        breakpoint()
+        assert spy.call_args[1]["time"] == np.float64(0.0)
+        assert spy.call_args[1]["current_step"] == 0