29 lines
940 B
TypeScript
29 lines
940 B
TypeScript
import type { RandomSource } from './random-source';
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import { rollInclusive } from './roll-range';
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function fixed(...values: number[]): RandomSource {
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let index = 0;
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return { next: () => values[index++] };
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}
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describe('rollInclusive', () => {
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it('maps the bottom of the random range to min and the top to max', () => {
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expect(rollInclusive(fixed(0), 4, 7)).toBe(4);
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expect(rollInclusive(fixed(0.999), 4, 7)).toBe(7);
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});
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it('spreads the random range evenly across every value in between', () => {
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expect(rollInclusive(fixed(0.25), 4, 7)).toBe(5);
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expect(rollInclusive(fixed(0.5), 4, 7)).toBe(6);
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expect(rollInclusive(fixed(0.5), 9, 15)).toBe(12);
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});
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it('never exceeds max even if the source yields exactly 1', () => {
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expect(rollInclusive(fixed(1), 9, 15)).toBe(15);
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});
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it('returns the single value when min equals max', () => {
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expect(rollInclusive(fixed(0.7), 1, 1)).toBe(1);
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});
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});
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