svoid test_gazelle_deepTransform() {
  assertEqualsVerbose("hello (people of the (bla bla)) world",
    gazelle_deepTransform(s -> eqic(s, "whole wide") ? "bla bla" : null, "hello (people of the (whole wide)) world"));
  assertEqualsVerbose("hello (people of the bla) world",
    gazelle_deepTransform(s -> eqic(s, "whole wide") ? "bla" : null, "hello (people of the (whole wide)) world"));
  assertEqualsVerbose("hello (people of the {bla blu}) world",
    gazelle_deepTransform(s -> eqic(s, "whole wide") ? "bla blu" : null, "hello (people of the {whole wide}) world"));
}