msg:
{ actual, expected, asString ? false, asJSON ? false, }:
if (if asString then
  toString actual == toString expected
else if asJSON then
  builtins.toJSON actual == builtins.toJSON expected
else
  actual == expected) then ''
    echo 'it ${msg}'
  '' else ''
    echo 'FAILED: ${msg}'
    echo '${builtins.toJSON expected}'
    echo '${builtins.toJSON actual}'
  ''