Low probability failure in test/test_extras/test_infixowl/test_restriction.py::test_restriction_str_and_hash

[aucampia]

Failures can be seen in these GitHub actions runs:

• https://github.com/RDFLib/rdflib/runs/7377860761?check_suite_focus=true
• https://github.com/RDFLib/rdflib/runs/7377860681?check_suite_focus=true

  ________________________ test_restriction_str_and_hash _________________________
  
  graph = <Graph identifier=http://example.org/vocab/context0 (<class 'rdflib.graph.Graph'>)>
  
      def test_restriction_str_and_hash(graph):
  
          r1 = (
              (Property(EXNS.someProp, baseType=OWL.DatatypeProperty))
              @ some
              @ (Class(EXNS.Foo))
          )
  
          assert str(r1) == "( ex:someProp SOME ex:Foo )"
  
          sg = Graph()
          sg.bind("ex", EXNS)
  
          r1.serialize(sg)
  
          assert r1.isPrimitive() is False
  >       assert len(str(r1.__hash__())) > 17
  E       AssertionError: assert 16 > 17
  E        +  where 16 = len('6777726393218724')
  E        +    where '6777726393218724' = str(6777726393218724)
  E        +      where 6777726393218724 = <bound method Restriction.__hash__ of ( ex:someProp SOME ex:Foo )>()
  E        +        where <bound method Restriction.__hash__ of ( ex:someProp SOME ex:Foo )> = ( ex:someProp SOME ex:Foo ).__hash__
  
  test/test_extras/test_infixowl/test_restriction.py:39: AssertionError

This command seems to reproduce this failure at least once, I got 3 failures on my last run:

for (( index=0; index<1000; index++ ));
do
  task test -- test/test_extras/test_infixowl/test_restriction.py::test_restriction_str_and_hash;
done

I'm guessing this is somehow related to python hash value which by default will be different for different instances.

CC: @gjhiggins

[aucampia]

Output from my computer:

============================================================================ test session starts ============================================================================
platform linux -- Python 3.10.5, pytest-7.1.2, pluggy-1.0.0
rootdir: /home/iwana/sw/d/github.com/iafork/rdflib.reviews, configfile: pyproject.toml
plugins: cov-3.0.0, repeat-0.9.1
collected 1 item                                                                                                                                                            

test/test_extras/test_infixowl/test_restriction.py F                                                                                                                  [100%]

================================================================================= FAILURES ==================================================================================
_______________________________________________________________________ test_restriction_str_and_hash _______________________________________________________________________

graph = <Graph identifier=http://example.org/vocab/context0 (<class 'rdflib.graph.Graph'>)>

    def test_restriction_str_and_hash(graph):
    
        r1 = (
            (Property(EXNS.someProp, baseType=OWL.DatatypeProperty))
            @ some
            @ (Class(EXNS.Foo))
        )
    
        assert str(r1) == "( ex:someProp SOME ex:Foo )"
    
        sg = Graph()
        sg.bind("ex", EXNS)
    
        r1.serialize(sg)
    
        assert r1.isPrimitive() is False
>       assert len(str(r1.__hash__())) > 17
E       AssertionError: assert 17 > 17
E        +  where 17 = len('56610119568990127')
E        +    where '56610119568990127' = str(56610119568990127)
E        +      where 56610119568990127 = <bound method Restriction.__hash__ of ( ex:someProp SOME ex:Foo )>()
E        +        where <bound method Restriction.__hash__ of ( ex:someProp SOME ex:Foo )> = ( ex:someProp SOME ex:Foo ).__hash__

test/test_extras/test_infixowl/test_restriction.py:39: AssertionError
========================================================================== short test summary info ==========================================================================
FAILED test/test_extras/test_infixowl/test_restriction.py::test_restriction_str_and_hash - AssertionError: assert 17 > 17
============================================================================= 1 failed in 0.15s =============================================================================
task: Failed to run task "test": exit status 1

[ghost]

It's my failure, I'm just guessing at how to test the result, hence the relative weakness of the length test - largely because I was merely focused on coverage, I assume __hash__() works.