Ensure no unexpected warnings are emitted while running test suite (post 1.1 release)

[lbianchi-lbl]

=============================== warnings summary ===============================
../../../../../opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/anaerobic_digester/tests/test_modified_ADM1_flowsheet_with_translators.py:38
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/anaerobic_digester/tests/test_modified_ADM1_flowsheet_with_translators.py:38: PytestRemovedIn9Warning: Marks applied to fixtures have no effect
  See docs: https://docs.pytest.org/en/stable/deprecations.html#applying-a-mark-to-a-fixture-function
    @pytest.mark.requires_idaes_solver

../../../../../opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/anaerobic_digester/tests/test_modified_ADM1_flowsheet_with_translators.py:117
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/anaerobic_digester/tests/test_modified_ADM1_flowsheet_with_translators.py:117: PytestRemovedIn9Warning: Marks applied to fixtures have no effect
  See docs: https://docs.pytest.org/en/stable/deprecations.html#applying-a-mark-to-a-fixture-function
    @pytest.mark.requires_idaes_solver

../../../../../opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/electroNP/tests/test_BSM2_electroNP_no_bioP.py:32
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/electroNP/tests/test_BSM2_electroNP_no_bioP.py:32: PytestRemovedIn9Warning: Marks applied to fixtures have no effect
  See docs: https://docs.pytest.org/en/stable/deprecations.html#applying-a-mark-to-a-fixture-function
    @pytest.fixture(scope="class")

../../../../../opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/full_water_resource_recovery_facility/test/test_BSM2_P_extension.py:38
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/full_water_resource_recovery_facility/test/test_BSM2_P_extension.py:38: PytestRemovedIn9Warning: Marks applied to fixtures have no effect
  See docs: https://docs.pytest.org/en/stable/deprecations.html#applying-a-mark-to-a-fixture-function
    @pytest.mark.requires_idaes_solver

../../../../../opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/full_water_resource_recovery_facility/test/test_BSM2_P_extension.py:131
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/watertap/flowsheets/full_water_resource_recovery_facility/test/test_BSM2_P_extension.py:131: PytestRemovedIn9Warning: Marks applied to fixtures have no effect
  See docs: https://docs.pytest.org/en/stable/deprecations.html#applying-a-mark-to-a-fixture-function
    @pytest.mark.requires_idaes_solver

flowsheets/RO_with_energy_recovery/tests/test_monte_carlo_sampling_RO_ERD.py::test_monte_carlo_sampling
flowsheets/RO_with_energy_recovery/tests/test_monte_carlo_sampling_RO_ERD.py::test_monte_carlo_sampling_with_files
flowsheets/RO_with_energy_recovery/tests/test_monte_carlo_sampling_RO_ERD.py::test_lhs_sampling
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/parameter_sweep/writer.py:82: UserWarning: No results will be writen to disk as h5_results_file_name and csv_results_file_name are both None
    warnings.warn(

flowsheets/lsrro/tests/test_lssro_multi_sweep.py::test_against_multisweep[1]
flowsheets/lsrro/tests/test_lssro_multi_sweep.py::test_against_multisweep[2]
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/parameter_sweep/writer.py:129: UserWarning: Too few points to perform interpolation.
    warnings.warn("Too few points to perform interpolation.")

unit_models/tests/test_generic_desalter.py::test_solve
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/_pytest/python.py:163: PytestReturnNotNoneWarning: Expected None, but unit_models/tests/test_generic_desalter.py::test_solve returned <pyomo.core.base.PyomoModel.ConcreteModel object at 0x7ff39e3c73e0>, which will be an error in a future version of pytest.  Did you mean to use `assert` instead of `return`?
    warnings.warn(

unit_models/tests/test_generic_separator.py::test_solve
  /opt/hostedtoolcache/Python/3.11.10/x64/lib/python3.11/site-packages/_pytest/python.py:163: PytestReturnNotNoneWarning: Expected None, but unit_models/tests/test_generic_separator.py::test_solve returned <pyomo.core.base.PyomoModel.ConcreteModel object at 0x7ff39f4d2490>, which will be an error in a future version of pytest.  Did you mean to use `assert` instead of `return`?
    warnings.warn(

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
========== 3058 passed, 12 skipped, 12 warnings in 1797.40s (0:29:57) ==========