def test_selection_logic():
    # Helper to test logic
    def get_selected_version_index(versions):
        found_best = False
        version_index = -1
        
        for i, v in enumerate(versions, start=0):
            if v.get("best", False):
                version_index = i
                found_best = True
                break
        
        if not found_best:
             # Default to the last one if not found
             version_index = len(versions) - 1
        
        return version_index

    # Case 1: No versions
    # Case 2: Versions, none best -> Last one
    versions_none_best = [
        {"title": "v1"},
        {"title": "v2"}
    ]
    assert get_selected_version_index(versions_none_best) == 1, "Should select last one (index 1)"
    
    # Case 3: Versions, first is best -> First one
    versions_first_best = [
        {"title": "v1", "best": True},
        {"title": "v2"}
    ]
    assert get_selected_version_index(versions_first_best) == 0, "Should select best one (index 0)"

    # Case 4: Versions, second is best -> Second one
    versions_second_best = [
        {"title": "v1"},
        {"title": "v2", "best": True},
        {"title": "v3"}
    ]
    assert get_selected_version_index(versions_second_best) == 1, "Should select best one (index 1)"
    
    print("All tests passed!")

if __name__ == "__main__":
    test_selection_logic()