react-native/Libraries/Lists/__tests__/FillRateHelper-test.js

121 lines
3.7 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*
* @format
* @emails oncall+react_native
*/
'use strict';
const FillRateHelper = require('FillRateHelper');
let rowFramesGlobal;
const dataGlobal = [
{key: 'header'},
{key: 'a'},
{key: 'b'},
{key: 'c'},
{key: 'd'},
{key: 'footer'},
];
function getFrameMetrics(index: number) {
const frame = rowFramesGlobal[dataGlobal[index].key];
return {length: frame.height, offset: frame.y, inLayout: frame.inLayout};
}
function computeResult({helper, props, state, scroll}): number {
helper.activate();
return helper.computeBlankness(
{
data: dataGlobal,
getItemCount: data2 => data2.length,
initialNumToRender: 10,
...(props || {}),
},
{first: 1, last: 2, ...(state || {})},
{offset: 0, visibleLength: 100, ...(scroll || {})},
);
}
describe('computeBlankness', function() {
beforeEach(() => {
FillRateHelper.setSampleRate(1);
FillRateHelper.setMinSampleCount(0);
});
it('computes correct blankness of viewport', function() {
const helper = new FillRateHelper(getFrameMetrics);
rowFramesGlobal = {
header: {y: 0, height: 0, inLayout: true},
a: {y: 0, height: 50, inLayout: true},
b: {y: 50, height: 50, inLayout: true},
};
let blankness = computeResult({helper});
expect(blankness).toBe(0);
blankness = computeResult({helper, state: {last: 1}});
expect(blankness).toBe(0.5);
blankness = computeResult({helper, scroll: {offset: 25}});
expect(blankness).toBe(0.25);
blankness = computeResult({helper, scroll: {visibleLength: 400}});
expect(blankness).toBe(0.75);
blankness = computeResult({helper, scroll: {offset: 100}});
expect(blankness).toBe(1);
});
it('skips frames that are not in layout', function() {
const helper = new FillRateHelper(getFrameMetrics);
rowFramesGlobal = {
header: {y: 0, height: 0, inLayout: false},
a: {y: 0, height: 10, inLayout: false},
b: {y: 10, height: 30, inLayout: true},
c: {y: 40, height: 40, inLayout: true},
d: {y: 80, height: 20, inLayout: false},
footer: {y: 100, height: 0, inLayout: false},
};
const blankness = computeResult({helper, state: {last: 4}});
expect(blankness).toBe(0.3);
});
it('sampling rate can disable', function() {
let helper = new FillRateHelper(getFrameMetrics);
rowFramesGlobal = {
header: {y: 0, height: 0, inLayout: true},
a: {y: 0, height: 40, inLayout: true},
b: {y: 40, height: 40, inLayout: true},
};
let blankness = computeResult({helper});
expect(blankness).toBe(0.2);
FillRateHelper.setSampleRate(0);
helper = new FillRateHelper(getFrameMetrics);
blankness = computeResult({helper});
expect(blankness).toBe(0);
});
it('can handle multiple listeners and unsubscribe', function() {
const listeners = [jest.fn(), jest.fn(), jest.fn()];
const subscriptions = listeners.map(listener =>
FillRateHelper.addListener(listener),
);
subscriptions[1].remove();
const helper = new FillRateHelper(getFrameMetrics);
rowFramesGlobal = {
header: {y: 0, height: 0, inLayout: true},
a: {y: 0, height: 40, inLayout: true},
b: {y: 40, height: 40, inLayout: true},
};
const blankness = computeResult({helper});
expect(blankness).toBe(0.2);
helper.deactivateAndFlush();
const info0 = listeners[0].mock.calls[0][0];
expect(info0.pixels_blank / info0.pixels_sampled).toBe(blankness);
expect(listeners[1]).not.toBeCalled();
const info1 = listeners[2].mock.calls[0][0];
expect(info1.pixels_blank / info1.pixels_sampled).toBe(blankness);
});
});