Add test folder to package data

Author: antonwolfy

setup.py

@@ -73,6 +73,8 @@ def _get_cmdclass():
             "libdpnp_backend_c.so",
             "dpnp_backend_c.lib",
             "dpnp_backend_c.dll",
+            "tests/*.*",
+            "tests/third_party/cupy/*.py",
         ]
     },
     include_package_data=True,