VirtualizeUtils-test.js
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/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
*
* @format
* @emails oncall+react_native
*/
'use strict';
const {elementsThatOverlapOffsets, newRangeCount} = require('VirtualizeUtils');
describe('newRangeCount', function() {
it('handles subset', function() {
expect(newRangeCount({first: 1, last: 4}, {first: 2, last: 3})).toBe(0);
});
it('handles forward disjoint set', function() {
expect(newRangeCount({first: 1, last: 4}, {first: 6, last: 9})).toBe(4);
});
it('handles reverse disjoint set', function() {
expect(newRangeCount({first: 6, last: 8}, {first: 1, last: 4})).toBe(4);
});
it('handles superset', function() {
expect(newRangeCount({first: 1, last: 4}, {first: 0, last: 5})).toBe(2);
});
it('handles end extension', function() {
expect(newRangeCount({first: 1, last: 4}, {first: 1, last: 8})).toBe(4);
});
it('handles front extension', function() {
expect(newRangeCount({first: 1, last: 4}, {first: 0, last: 4})).toBe(1);
});
it('handles forward insersect', function() {
expect(newRangeCount({first: 1, last: 4}, {first: 3, last: 6})).toBe(2);
});
it('handles reverse intersect', function() {
expect(newRangeCount({first: 3, last: 6}, {first: 1, last: 4})).toBe(2);
});
});
describe('elementsThatOverlapOffsets', function() {
it('handles fixed length', function() {
const offsets = [0, 250, 350, 450];
function getFrameMetrics(index: number) {
return {
length: 100,
offset: 100 * index,
};
}
expect(elementsThatOverlapOffsets(offsets, 100, getFrameMetrics)).toEqual([
0,
2,
3,
4,
]);
});
it('handles variable length', function() {
const offsets = [150, 250, 900];
const frames = [
{offset: 0, length: 50},
{offset: 50, length: 200},
{offset: 250, length: 600},
{offset: 850, length: 100},
{offset: 950, length: 150},
];
expect(
elementsThatOverlapOffsets(offsets, frames.length, ii => frames[ii]),
).toEqual([1, 1, 3]);
});
it('handles out of bounds', function() {
const offsets = [150, 900];
const frames = [
{offset: 0, length: 50},
{offset: 50, length: 150},
{offset: 250, length: 100},
];
expect(
elementsThatOverlapOffsets(offsets, frames.length, ii => frames[ii]),
).toEqual([1]);
});
it('errors on non-increasing offsets', function() {
const offsets = [150, 50];
const frames = [
{offset: 0, length: 50},
{offset: 50, length: 150},
{offset: 250, length: 100},
];
expect(() => {
elementsThatOverlapOffsets(offsets, frames.length, ii => frames[ii]);
}).toThrowErrorMatchingSnapshot();
});
});