Add tests for dldevice and sycldevice interchange functions

dpctl/tests/test_usm_ndarray_dlpack.py

@@ -826,3 +826,38 @@ def test_generic_container():
     assert isinstance(Z, dpt.usm_ndarray)
     assert Z._pointer == X._pointer
     assert Z.device == X.device
+
+
+def test_sycldevice_to_dldevice(all_root_devices):
+    for sycl_dev in all_root_devices:
+        dev = dpt.sycldevice_to_dldevice(sycl_dev)
+        assert type(dev) is tuple
+        assert len(dev) == 2
+        assert dev[0] == device_oneAPI
+        assert dev[1] == all_root_devices.index(sycl_dev)
+
+
+def test_dldevice_to_sycldevice(all_root_devices):
+    for sycl_dev in all_root_devices:
+        dldev = dpt.empty(0, device=sycl_dev).__dlpack_device__()
+        dev = dpt.dldevice_to_sycldevice(dldev)
+        assert type(dev) is dpctl.SyclDevice
+        assert dev == all_root_devices[dldev[1]]
+
+
+def test_dldevice_conversion_arg_validation():
+    bad_dldevice_type = (dpt.DLDeviceType.kDLCPU, 0)
+    with pytest.raises(ValueError):
+        dpt.dldevice_to_sycldevice(bad_dldevice_type)
+
+    bad_dldevice_len = bad_dldevice_type + (0,)
+    with pytest.raises(ValueError):
+        dpt.dldevice_to_sycldevice(bad_dldevice_len)
+
+    bad_dldevice = dict()
+    with pytest.raises(TypeError):
+        dpt.dldevice_to_sycldevice(bad_dldevice)
+
+    bad_sycldevice = dict()
+    with pytest.raises(TypeError):
+        dpt.sycldevice_to_dldevice(bad_sycldevice)