TST: Cover additional NEP 50 scalar paths

Especially adding coverage also for the power operator which
does not share its code perfectly.

numpy/core/tests/test_nep50_promotions.py

@@ -4,7 +4,10 @@
 is adopted in the main test suite.  A few may be moved elsewhere.
 """
 
+import operator
+
 import numpy as np
+
 import pytest
 
 
@@ -123,6 +126,19 @@ def test_nep50_weak_integers_with_inexact(dtype):
         assert res == np.inf
 
 
+@pytest.mark.parametrize("op", [operator.add, operator.pow, operator.eq])
+def test_weak_promotion_scalar_path(op):
+    # Some additional paths excercising the weak scalars.
+    np._set_promotion_state("weak")
+
+    res = op(np.uint8(3), 5)
+    assert res == op(3, 5)
+    assert res.dtype == np.uint8 or res.dtype == bool
+
+    with pytest.raises(OverflowError):
+        op(np.uint8(3), 1000)
+
+
 def test_nep50_complex_promotion():
     np._set_promotion_state("weak")