This test is specified as

   testset:

      suffix: expl

      nsize: {{1 2}}

      filter: grep -v "MPI processes" | grep -v " type:" | grep -v "Mat Object"

      args: -ksp_converged_reason -view_explicit_mat -pc_type none -ksp_type {{cg gmres}}

      test:

        args: -mat_type aij

      test:

        requires: hypre

        args: -mat_type hypre

It triggers an error here https://gitlab.com/petsc/petsc/-/jobs/1519558357, with a CI configuration without hypre.

Other testset instances works fine if any “require:" is both specified in the testset body and in the specific test.