[Misc] Consolidate ModelConfig code related to HF config (#10104)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

tests/test_config.py

@@ -165,3 +165,41 @@ def test_rope_customization():
     assert getattr(longchat_model_config.hf_config, "rope_scaling",
                    None) == TEST_ROPE_SCALING
     assert longchat_model_config.max_model_len == 4096
+
+
+@pytest.mark.parametrize(("model_id", "is_encoder_decoder"), [
+    ("facebook/opt-125m", False),
+    ("facebook/bart-base", True),
+    ("meta-llama/Llama-3.2-1B", False),
+    ("meta-llama/Llama-3.2-11B-Vision", True),
+])
+def test_is_encoder_decoder(model_id, is_encoder_decoder):
+    config = ModelConfig(
+        model_id,
+        task="auto",
+        tokenizer=model_id,
+        tokenizer_mode="auto",
+        trust_remote_code=False,
+        dtype="float16",
+        seed=0,
+    )
+
+    assert config.is_encoder_decoder == is_encoder_decoder
+
+
+@pytest.mark.parametrize(("model_id", "uses_mrope"), [
+    ("facebook/opt-125m", False),
+    ("Qwen/Qwen2-VL-2B-Instruct", True),
+])
+def test_uses_mrope(model_id, uses_mrope):
+    config = ModelConfig(
+        model_id,
+        task="auto",
+        tokenizer=model_id,
+        tokenizer_mode="auto",
+        trust_remote_code=False,
+        dtype="float16",
+        seed=0,
+    )
+
+    assert config.uses_mrope == uses_mrope