public void Associative()
{
var a = Sigo.Create(1,
"a/x", "ax",
"a/y", "ay",
"b", "b"
);
// add "/a/z": az
var b = Sigo.Create(0, "a/z", "az");
// change "/b": "b+"
var c = Sigo.Create(0, "b", "b+");
var abc1 = Sigo.Merge(Sigo.Merge(a, b), c);
var abc2 = Sigo.Merge(a, Sigo.Merge(b, c));
var expect = Sigo.Create(3,
"a/x", "ax",
"a/y", "ay",
"a/z", "az",
"b", "b+"
);
SigoAssert.Equal(abc1, abc2);
SigoAssert.Equal(expect, abc2);
}