Trac #30112: doctest added

Author: Michael Jung

src/sage/manifolds/differentiable/scalarfield_algebra.py

@@ -406,6 +406,8 @@ def _coerce_map_from_(self, other):
             sage: CM = M.scalar_field_algebra()
             sage: CM._coerce_map_from_(SR)
             True
+            sage: CM._coerce_map_from_(X.function_ring())
+            True
             sage: U = M.open_subset('U', coord_def={X: x>0})
             sage: CU = U.scalar_field_algebra()
             sage: CM._coerce_map_from_(CU)