<!DOCTYPE html> <title>window.requestIdleCallback deals with timeouts correctly</title> <meta name="timeout" content="long"> <link rel="author" title="Ross McIlroy" href="mailto:rmcilroy@chromium.org" /> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script> async_test(function() { // Check whether requestIdleCallback with a timeout works when the event loop // is busy. var busy_loop_iterations_remaining = 10; // Should take 20 * 40 = 400ms var idle_callback_scheduled; var idle_callback = this.step_func_done(function(deadline) { assert_false(deadline.didTimeout, "IdleDeadline.didTimeout MUST be false if requestIdleCallback wasn't scheduled due to a timeout"); assert_equals(busy_loop_iterations_remaining, 0, "Busy event loop should be finished by the time we get scheduled"); }); var busy_loop_iterations_remaining = 10; // Should take 20 * 40 = 400ms step_timeout(this.step_func(function busyLoop() { var start_time = performance.now(); if (!idle_callback_scheduled) { idle_callback_scheduled = start_time; requestIdleCallback(idle_callback); } // Use up more than a frames worth of budget. while (performance.now() - start_time < 40) { } if (busy_loop_iterations_remaining > 0) { busy_loop_iterations_remaining--; step_timeout(busyLoop); } })); }, 'requestIdleCallback not scheduled when event loop is busy.'); async_test(function() { // Check whether requestIdleCallback with a timeout works when the event loop // is busy. var busy_loop_iterations_remaining = 10; // Should take 20 * 40 = 400ms var timeout = 200; var idle_callback_scheduled; var idle_callback = this.step_func_done(function(deadline) { var time_delta = performance.now() - idle_callback_scheduled; assert_true(time_delta >= timeout, "Should only have been run after timeout"); assert_true(deadline.timeRemaining() == 0, "IdleDeadline.timeRemaining MUST be equal to zero if requestIdleCallback was scheduled due to a timeout"); assert_true(deadline.didTimeout, "IdleDeadline.didTimeout MUST be true if requestIdleCallback was scheduled due to a timeout"); assert_true(busy_loop_iterations_remaining > 0, "Busy event loop should still be going"); }); step_timeout(this.step_func(function busyLoop() { var start_time = performance.now(); if (!idle_callback_scheduled) { idle_callback_scheduled = start_time; requestIdleCallback(idle_callback, { timeout: timeout }); } // Use up more than a frames worth of budget. while (performance.now() - start_time < 40) { } if (busy_loop_iterations_remaining > 0) { busy_loop_iterations_remaining--; step_timeout(busyLoop); } })); }, 'requestIdleCallback scheduled with timeout when event loop is busy.'); </script> <h1>Test of requestIdleCallback timeout behavior</h1> <div id="log"></div>