[CI] Add unittest for activation, native_paddle_backend, w4a8, w4afp8, platforms/utils (#4812)

* add unnitest for activation, native_paddle_backend, w4a8, w4afp8, platforms/utils

* Remove activation function retrieval tests

Removed tests for valid and unsupported activation function retrieval.

* move w4a8, w4afp8 to quantization

* fix code style

tests/platforms/test_utils.py

@@ -0,0 +1,31 @@
+import unittest
+from unittest.mock import patch
+
+import numpy as np
+import paddle
+
+from fastdeploy.platforms.utils import convert_to_npu_dequant_scale
+
+
+class TestConvertToNpuDequantScale(unittest.TestCase):
+
+    def test_npu_not_available(self):
+        with patch("paddle.is_compiled_with_custom_device", return_value=False):
+            x = paddle.to_tensor([1.0, 2.0, 3.0], dtype=paddle.float32)
+            out = convert_to_npu_dequant_scale(x)
+            self.assertTrue((out.numpy() == x.numpy()).all())
+
+    def test_npu_available(self):
+        with patch("paddle.is_compiled_with_custom_device", return_value=True):
+            x = paddle.to_tensor([1, 2, 3], dtype=paddle.float32)
+            out = convert_to_npu_dequant_scale(x)
+            self.assertEqual(out.dtype, paddle.int64)
+            # Verify scaled output matches expected NPU dequantization format
+            arr = x.numpy()
+            new_deq_scale = np.stack([arr.reshape(-1, 1), np.zeros_like(arr).reshape(-1, 1)], axis=-1).reshape(-1)
+            expected = np.frombuffer(new_deq_scale.tobytes(), dtype=np.int64)
+            self.assertTrue((out.numpy() == expected).all())
+
+
+if __name__ == "__main__":
+    unittest.main()