Split test_healthsystem.py into two files to enable parallel running and so speed up testing.

[tbhallett]

Here I propose a split of the test_healthsystem.py into:

1. test_healthsystem_general_and_mode1.py: This test file is focussed on the overall function of the module and its behaviour in Mode 1.
2. test_healthsystem_mode2.py: This test file is focussed on behaviour in Mode 2 (including rescaling and clinics).

This feels like a logical way to split the tests. However, the first of these still contains more tests, so may still take much longer. If necessary, a further cut could be made!

[tamuri]

Looks like mode2 test took only 4 mins!

================================ resource usage ================================
tests/test_healthsystem_mode2.py::test_run_in_mode_2_with_capacity[83563095832589325021] (call) running time: 0:01:02
tests/test_healthsystem_mode2.py::test_run_in_mode_2_with_no_capacity[83563095832589325021] (call) running time: 37.705 seconds
tests/test_healthsystem_mode2.py::test_mode_appt_constraints2_on_healthsystem[83563095832589325021] (call) running time: 3.262 seconds
tests/test_healthsystem_mode2.py::test_run_in_mode_2_with_capacity_with_health_seeking_behaviour[83563095832589325021] (call) running time: 0:01:14
tests/test_healthsystem_mode2.py::test_mode_2_clinics[83563095832589325021] (call) running time: 0:01:23
================= 5 passed, 299 warnings in 265.76s (0:04:25) ==================

[tbhallett]

Ok, will try something else!

[tamuri]

The big ones are these three:

test_policy_has_no_effect_on_mode1 running time: 0:30:09
test_which_hsi_can_run running time: 0:17:54
test_scaling_up_HRH_using_yearly_scaling_and_scaling_by_level_together running time: 0:13:04

[tbhallett]

Now completing in
test_healthsystem_general: 51 minutes
test_healthsystem_hrh: 38 minutes

So, could split test_healthsystem_general into two....

[tamuri]

Thanks, Tim. This cuts the current test runtime in about half - merging!