describe("S.root(dispose)", function () {
    it("disables updates and sets computation's value to undefined", function () {
		S.root(function (dispose) {
			var c = 0,
				d = S.data(0),
				f = S(function () { c++; return d(); });

			expect(c).toBe(1);
			expect(f()).toBe(0);

			d(1);

			expect(c).toBe(2);
			expect(f()).toBe(1);

			dispose();

			d(2);

			expect(c).toBe(2);
			expect(f()).toBe(1);
		});
    });

	// unconventional uses of dispose -- to insure S doesn't behaves as expected in these cases

	it("works from the body of its own computation", function () {
		S.root(function (dispose) {
			var c = 0,
				d = S.data(0),
				f = S(function () { c++; if (d()) dispose(); d(); });

			expect(c).toBe(1);

			d(1);

			expect(c).toBe(2);

			d(2);

			expect(c).toBe(2);
		});
	});

	it("works from the body of a subcomputation", function () {
		S.root(function (dispose) {
			var c = 0,
				d = S.data(0),
				f = S(function () {
					c++;
					d();
					S(function () {	if (d()) dispose(); });
				});

			expect(c).toBe(1);

			d(1);

			expect(c).toBe(2);

			d(2);

			expect(c).toBe(2);
		});
	});
});