Tests that are needed, should be moved, or should be reformatted

[elenya-grant]

While I was working on Pr #463 I found a good handful of tests that are missing, formatted to use unittest rather than pytest or are integration tests that should be relocated out of a tech-specific folder.

Models that need more thorough unit tests

There are no unit tests for the below models, only tests that may exist (from PR #463) are just ensuring that the outputs are populated, not checking specific values or logic (do outputs change as expected if inputs change)

• methanol models (smr and co2h)
• pem electrolyzer tests for the performance model decoupled from the cost model (h2integrate/converters/hydrogen/pem_electrolyzer.py)
• simple steel performance model h2integrate/converters/steel/steel.py
• hydro power h2integrate/converters/water_power/hydro_plant_run_of_river.py

Tests that are integration tests and should be moved

• h2integrate/converters/ammonia/test/test_ammonia_synloop_model.py::test_size_mode_outputs
• h2integrate/converters/hydrogen/test/test_size_modes.py::test_resize_by_max_feedstock
• h2integrate/converters/hydrogen/test/test_size_modes.py::test_resize_by_max_commodity

Tests that should be reformatted to use pytest

• h2integrate/converters/co2/marine/test/test_doc.py
• h2integrate/converters/grid/test/test_grid.py
• h2integrate/converters/co2/marine/test/test_oae.py
• h2integrate/finances/test/test_finances.py
• h2integrate/core/test/test_utilities.py
• h2integrate/core/test/test_feedstocks.py