Add UT for FP4 Copy

Author: CuiYifeng

test/regressions/test_copy.py

@@ -14,8 +14,8 @@
 class TestSimpleCopy(TestCase):
     @dtypes(*float8_types_and(torch.float8_e8m0fnu, torch.float32))
     def test_copy_and_clone(self, dtype):
-        a_cpu = torch.randn(16, 64, 28, 28)
-        b_cpu = torch.randn(16, 64, 28, 28)
+        a_cpu = torch.randn(16, 64, 28, 28).to(dtype)
+        b_cpu = torch.randn(16, 64, 28, 28).to(dtype)
         a_xpu = a_cpu.to(xpu_device)
         b_xpu = b_cpu.to(xpu_device)
         # naive
@@ -27,6 +27,22 @@ def test_copy_and_clone(self, dtype):
         b_xpu = a_xpu.clone(memory_format=torch.channels_last)
         self.assertEqual(b_cpu, b_xpu.to(cpu_device))
 
+    def test_copy_and_clone_float4(self):
+        # Float4_e2m1fn_x2 copy is not implemented by CPU
+        a_cpu = torch.randn(16, 64, 28, 28).to(torch.uint8)
+        b_cpu = torch.randn(16, 64, 28, 28).to(torch.uint8)
+        a_xpu = a_cpu.to(xpu_device).view(torch.float4_e2m1fn_x2)
+        b_xpu = b_cpu.to(xpu_device).view(torch.float4_e2m1fn_x2)
+
+        b_cpu.copy_(a_cpu)
+        b_xpu.copy_(a_xpu)
+        # Float4_e2m1fn_x2 compare is not implemented CPU
+        self.assertEqual(b_cpu, b_xpu.view(torch.uint8).to(cpu_device))
+
+        b_cpu = a_cpu.clone(memory_format=torch.channels_last)
+        b_xpu = a_xpu.clone(memory_format=torch.channels_last)
+        self.assertEqual(b_cpu, b_xpu.view(torch.uint8).to(cpu_device))
+
 
 instantiate_device_type_tests(TestSimpleCopy, globals(), only_for="xpu", allow_xpu=True)