discourse/test/javascripts/lib/debounce_test.js

83 lines
2.1 KiB
JavaScript

var clock, original, debounced;
var firedOnce = function(message) {
ok(original.calledOnce, message);
};
var firedTwice = function(message) {
ok(original.calledTwice, message);
};
var notFired = function(message) {
ok(!original.called, message);
};
module("Discourse.debounce", {
setup: function() {
clock = sinon.useFakeTimers();
original = sinon.spy();
debounced = Discourse.debounce(original, 100);
},
teardown: function() {
clock.restore();
}
});
test("delays function execution till the end of the timeout", function() {
debounced();
notFired("immediately after calling debounced function nothing happens");
clock.tick(99);
notFired("just before the end of the timeout still nothing happens");
clock.tick(1);
firedOnce("exactly at the end of the timeout the function is executed");
});
test("executes delayed function only once, no matter how many times debounced function is called during the timeout", function() {
debounced();
debounced();
clock.tick(100);
firedOnce("second call was supressed");
});
test("prolongs the timeout when the debounced function is called for the second time during the timeout", function() {
debounced();
clock.tick(50);
debounced();
clock.tick(50);
notFired("at the end of the original timeout nothing happens");
clock.tick(50);
firedOnce("function is executed exactly at the end of the prolonged timeout");
});
test("preserves last call's context and params when executing delayed function", function() {
var firstObj = {};
var secondObj = {};
debounced.call(firstObj, "first");
debounced.call(secondObj, "second");
clock.tick(100);
ok(original.calledOn(secondObj), "the context of the last of two subsequent calls is preserved");
ok(original.calledWithExactly("second"), "param passed during the last of two subsequent calls is preserved");
});
test("can be called again after timeout passes", function() {
var firstObj = {};
var secondObj = {};
debounced.call(firstObj, "first");
clock.tick(100);
debounced.call(secondObj, "second");
clock.tick(100);
firedTwice();
});