remove cross tokenization and fix location of configs

atroposlib/tests/test_teacher_distillation_env.py

@@ -67,3 +67,29 @@ async def test_attach_teacher_distillation_failure_drops_payload():
     out = await TeacherDistillationEnv._attach_teacher_distillation(env, group)
     assert out["distill_token_ids"] is None
     assert out["distill_logprobs"] is None
+
+
+def test_teacher_tokenizer_mismatch_raises(monkeypatch):
+    env = object.__new__(_ConcreteTeacherEnv)
+
+    class _StudentTokenizer:
+        name_or_path = "student-model"
+
+        def get_vocab(self):
+            return {"a": 1}
+
+    class _TeacherTokenizer:
+        def get_vocab(self):
+            return {"b": 1}
+
+    env.tokenizer = _StudentTokenizer()
+    monkeypatch.setattr(
+        "transformers.AutoTokenizer.from_pretrained",
+        lambda *args, **kwargs: _TeacherTokenizer(),
+    )
+
+    with pytest.raises(ValueError, match="Cross-tokenizer distillation is not supported"):
+        TeacherDistillationEnv._validate_teacher_tokenizer_compatibility(
+            env,
+            teacher_tokenizer_name="teacher-model",
+        )