py-torch: make sure unit tests are registered (#15765)

var/spack/repos/builtin/packages/py-torch/package.py

@@ -287,9 +287,11 @@ def enable_or_disable(variant, keyword='USE', var=None, newer=False):
         enable_or_disable('zstd', newer=True)
         enable_or_disable('tbb', newer=True)
 
-    def test(self):
-        pass
-
     def install_test(self):
         with working_dir('test'):
             python('run_test.py')
+
+    # Tests need to be re-added since `phases` was overridden
+    run_after('install')(
+        PythonPackage._run_default_install_time_test_callbacks)
+    run_after('install')(PythonPackage.sanity_check_prefix)