Principle of the test
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This test is used to validate the emission of some messages by the FACTORISER or RESOUDRE commands in the case of a symmetric matrix:


* First case: a blockage is missing. In this case we get FACTOR_20 /77 for LDLT, MULT_FRONT and MUMPS when :math:`\mathrm{NPREC}>0` and FACTOR_57 for MUMPS when :math:`\mathrm{NPREC}<0`.


* Second case: there is an overabundant blockage. We get FACTOR_21 /76 for LDLT, MULT_FRONT, and MUMPS when :math:`\mathrm{NPREC}>0` and FACTOR_42 for MUMPS when :math:`\mathrm{NPREC}<0`.


* Last case: we check that we are sending the message FACTOR_80 when using the parameter TYPE_RESOL =' SYMDEF 'of the solver MUMPS when the matrix to be inverted is not symmetric definite positive.