feat(pt_expt): load plugin entry points

deepmd/pt_expt/__init__.py

@@ -1 +1,7 @@
 # SPDX-License-Identifier: LGPL-3.0-or-later
+
+from deepmd.utils.entry_point import (
+    load_entry_point,
+)
+
+load_entry_point("deepmd.pt_expt")

source/tests/pt_expt/test_plugin.py

@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+import importlib
+import importlib.metadata
+import sys
+
+
+class _FakeEntryPoint:
+    def __init__(self, calls):
+        self.calls = calls
+
+    def load(self):
+        self.calls.append("load")
+
+
+def test_pt_expt_loads_plugin_entry_points(monkeypatch):
+    groups = []
+    calls = []
+
+    def fake_entry_points(*, group=None):
+        groups.append(group)
+        return [_FakeEntryPoint(calls)]
+
+    monkeypatch.setattr(importlib.metadata, "entry_points", fake_entry_points)
+    sys.modules.pop("deepmd.pt_expt", None)
+
+    try:
+        importlib.import_module("deepmd.pt_expt")
+    finally:
+        sys.modules.pop("deepmd.pt_expt", None)
+
+    assert groups == ["deepmd.pt_expt"]
+    assert calls == ["load"]