Some microphysics if-else branches are not exercised

[charleskawczynski]

I was looking at refactoring a bit of the microphysics code, specifically here. What I came up with looks like

struct Rain1M end
struct RainCutoff end
struct RainNone end

function compute_qr_src(::Rain1M, ts, liq_type, rain_type, q_pt, qr, ρ0, dt)
    qr_src1 = q_pt.liq / dt
    qr_src2 = CM1.conv_q_liq_to_q_rai(ts.param_set, q_pt.liq) +
              CM1.accretion(ts.param_set, liq_type, rain_type, q_pt.liq, qr, ρ0)
    return min(qr_src1, qr_src2)
end

function compute_qr_src(::RainCutoff, ts, liq_type, rain_type, q_pt, qr, ρ0, dt)
    qsat = TD.q_vap_saturation(ts)
    qr_src1 = q_pt.liq / dt
    qr_src2 = -CM0.remove_precipitation(ts.param_set, q_pt, qsat)
    return min(qr_src1, qr_src2)
end

compute_qr_src(::RainNone, ts, liq_type, rain_type, q_pt, qr, ρ0, dt) = 0

function microphysics_rain_src(param_set::APS, rain_model, q_pt, qr, area, ρ0, dt, ts)
    area > 0.0 && return mph_struct(;qr_src=0, thl_rain_src=0)
    qr_src = compute_qr_src(rain_model, ts, liq_type, rain_type, q_pt, qr, ρ0, dt)
    thl_rain_src = rain_source_to_θ_liq(ts, qr_src)
    return mph_struct(;thl_rain_src, qr_src)
end

and I was going to open a PR, but I then noticed that liq_type and rain_type are not defined, and so I thought it might be better to just copy this code here and point this out.

[trontrytel]

@charleskawczynski - I think that the recent microphysics related PRs solved this issue? Could you double check?

[charleskawczynski]

Yes, I believe so. Closing.