tidier scr unit conversion

[jasmineirx]

in valid_units("scr") we accept either "mg_dl" or "mg/dl", but we convert from molar mass if the unit is anything but "mg/dl". This PR instead looks for the presence of "mol" in the unit to identify if the units are molar and should be converted, catching a possible edge case.

this does not affect any production code since we standardize units elsewhere, however I think this is a cleaner approach.

clinPK::valid_units("scr")
#>  [1] "mg/dl"      "mg_dl"      "micromol/l" "micromol_l" "micromol"  
#>  [6] "mmol"       "mumol/l"    "umol/l"     "mumol_l"    "umol_l"

^{Created on 2024-09-24 with reprex v2.1.1}

[dominic-irx]

From the valid units list, are micromol and mmol equal to umol/L?

[dominic-irx]

lgtm just one question

[jasmineirx]

good catch, I used a function instead, which accounts for all the differences. However, we now use the correct molecular conversion factor instead of the rounded factor. we might see some test values change. I can monitor it.