Trac #29971: Make categories doctests ready for random seeds

This ticket makes
{{{
sage -t --long --random-seed=n src/sage/categories/
}}}
pass for different values `n` than just `0`.

URL: https://trac.sagemath.org/29971
Reported by: gh-kliem
Ticket author(s): Jonathan Kliem
Reviewer(s): Markus Wageringel

Author: Release Manager

src/sage/categories/finite_enumerated_sets.py

@@ -479,10 +479,13 @@ def _random_element_from_unrank(self):
             EXAMPLES::
 
                 sage: C = FiniteEnumeratedSets().example()
-                sage: C.random_element()
-                1
-                sage: C._random_element_from_unrank()
-                2
+                sage: n = C.random_element()
+                sage: n in C
+                True
+
+                sage: n = C._random_element_from_unrank()
+                sage: n in C
+                True
 
             TODO: implement _test_random which checks uniformness
             """

src/sage/categories/modules_with_basis.py

@@ -1276,20 +1276,22 @@ def random_element(self, n=2):
 
             EXAMPLES::
 
-                sage: DihedralGroup(6).algebra(QQ).random_element()
-                -1/95*() - 1/2*(1,4)(2,5)(3,6)
+                sage: x = DihedralGroup(6).algebra(QQ).random_element()
+                sage: x.parent() is DihedralGroup(6).algebra(QQ)
+                True
 
             Note, this result can depend on the PRNG state in libgap in a way
             that depends on which packages are loaded, so we must re-seed GAP
             to ensure a consistent result for this example::
 
                 sage: libgap.set_seed(0)
                 0
-                sage: SU(2, 13).algebra(QQ).random_element(1)
-                1/2*[       1  9*a + 2]
-                [2*a + 12        2]
-                sage: CombinatorialFreeModule(ZZ, Partitions(4)).random_element() # random
-                2*B[[2, 1, 1]] + B[[2, 2]]
+                sage: m = SU(2, 13).algebra(QQ).random_element(1)
+                sage: m.parent() is SU(2, 13).algebra(QQ)
+                True
+                sage: p = CombinatorialFreeModule(ZZ, Partitions(4)).random_element()
+                sage: p.parent() is CombinatorialFreeModule(ZZ, Partitions(4))
+                True
 
             TESTS: