There are some modules where test coverage can improve. Let's target step by step:

io:

• import and export functionality, starts with Add rudimentary test for import and export functionality #229

components:

• madd()
• mremove()
• copy()
• __getitem__() aka network[:,:]
• consistency_check()

linopt:

• get_sol()
• get_dual()

linopf:

• ramp limits
• store constraints
• global constraints
• ilopf()

opf:

• ramp limits, shut down, start up

pf:

• sub_network_pf_singlebus()
• aggregate_multi_graph()

as well as

• networkclustering
• plots
• stats