[chat-template] Unify tests and clean up 🧼 (#37275)

* fix tests and some clean up

* make one general test for each modality

* remove redundant merging of kwargs

* edge cases

* dont enforce slow when reloading

* fix gemma3 tests

* has to adapt llama 4 after rebase

* remove also from overriden tests

* should be green now

tests/models/llava_next/test_processor_llava_next.py

@@ -78,23 +78,6 @@ class LlavaNextProcessorTest(ProcessorTesterMixin, unittest.TestCase):
         processor_dict = self.prepare_processor_dict()
         self.assertTrue(processor_loaded.chat_template == processor_dict.get("chat_template", None))
 
-    def test_chat_template(self):
-        processor = AutoProcessor.from_pretrained("llava-hf/llava-v1.6-vicuna-7b-hf")
-        expected_prompt = "USER: <image>\nWhat is shown in this image? ASSISTANT:"
-
-        messages = [
-            {
-                "role": "user",
-                "content": [
-                    {"type": "image"},
-                    {"type": "text", "text": "What is shown in this image?"},
-                ],
-            },
-        ]
-
-        formatted_prompt = processor.apply_chat_template(messages, add_generation_prompt=True)
-        self.assertEqual(expected_prompt, formatted_prompt)
-
     def test_image_token_filling(self):
         processor = AutoProcessor.from_pretrained("llava-hf/llava-v1.6-vicuna-7b-hf")
         processor.patch_size = 14