[Misc][LoRA] Add --lora-target-modules to restrict LoRA to specific modules (#34984)

Signed-off-by: Bhoomit Vasani <bhoomit.2010@gmail.com>
Co-authored-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/entrypoints/openai/test_cli_args.py

@@ -291,3 +291,32 @@ def test_served_model_name_parsing(tmp_path, vllm_parser, args, raises):
     else:
         with pytest.raises(raises):
             vllm_parser.parse_args(args=args)
+
+
+### Tests for LoRA target modules parsing
+def test_lora_target_modules_single(serve_parser):
+    """Test parsing single lora-target-modules argument"""
+    args = serve_parser.parse_args(
+        args=["--enable-lora", "--lora-target-modules", "o_proj"]
+    )
+    assert args.lora_target_modules == ["o_proj"]
+
+
+def test_lora_target_modules_multiple(serve_parser):
+    """Test parsing multiple lora-target-modules arguments"""
+    args = serve_parser.parse_args(
+        args=[
+            "--enable-lora",
+            "--lora-target-modules",
+            "o_proj",
+            "qkv_proj",
+            "down_proj",
+        ]
+    )
+    assert args.lora_target_modules == ["o_proj", "qkv_proj", "down_proj"]
+
+
+def test_lora_target_modules_default_none(serve_parser):
+    """Test that lora-target-modules defaults to None"""
+    args = serve_parser.parse_args(args=[])
+    assert args.lora_target_modules is None