e663504df1
For negative number this previously rounded towards zero instead of the intended always rounding down.
75 lines
2 KiB
JavaScript
75 lines
2 KiB
JavaScript
test("basic numeric shifting", () => {
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expect(0 << 0).toBe(0);
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expect(0 << 1).toBe(0);
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expect(0 << 2).toBe(0);
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expect(0 << 3).toBe(0);
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expect(0 << 4).toBe(0);
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expect(0 << 5).toBe(0);
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expect(1 << 0).toBe(1);
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expect(1 << 1).toBe(2);
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expect(1 << 2).toBe(4);
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expect(1 << 3).toBe(8);
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expect(1 << 4).toBe(16);
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expect(1 << 5).toBe(32);
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expect(2 << 0).toBe(2);
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expect(2 << 1).toBe(4);
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expect(2 << 2).toBe(8);
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expect(2 << 3).toBe(16);
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expect(2 << 4).toBe(32);
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expect(2 << 5).toBe(64);
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expect(3 << 0).toBe(3);
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expect(3 << 1).toBe(6);
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expect(3 << 2).toBe(12);
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expect(3 << 3).toBe(24);
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expect(3 << 4).toBe(48);
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expect(3 << 5).toBe(96);
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expect(4 << 0).toBe(4);
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expect(4 << 1).toBe(8);
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expect(4 << 2).toBe(16);
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expect(4 << 3).toBe(32);
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expect(4 << 4).toBe(64);
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expect(4 << 5).toBe(128);
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expect(5 << 0).toBe(5);
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expect(5 << 1).toBe(10);
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expect(5 << 2).toBe(20);
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expect(5 << 3).toBe(40);
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expect(5 << 4).toBe(80);
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expect(5 << 5).toBe(160);
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expect(0xffffffff << 0).toBe(-1);
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expect(0xffffffff << 16).toBe(-65536);
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expect(0xffff0000 << 16).toBe(0);
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expect(0xffff0000 << 15).toBe(-2147483648);
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});
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test("shifting with non-numeric values", () => {
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let x = 3;
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let y = 7;
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expect("42" << 6).toBe(2688);
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expect(x << y).toBe(384);
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expect(x << [[[[12]]]]).toBe(12288);
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expect(undefined << y).toBe(0);
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expect("a" << "b").toBe(0);
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expect(null << null).toBe(0);
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expect(undefined << undefined).toBe(0);
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expect(NaN << NaN).toBe(0);
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expect(NaN << 6).toBe(0);
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expect(Infinity << Infinity).toBe(0);
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expect(-Infinity << Infinity).toBe(0);
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});
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describe("logical left shift on big ints", () => {
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expect(3n << -1n).toBe(1n);
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expect(3n << -2n).toBe(0n);
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expect(-3n << -1n).toBe(-2n);
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expect(-3n << -2n).toBe(-1n);
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expect(-3n << -128n).toBe(-1n);
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expect(3n << 6n).toBe(192n);
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expect(3n << 0n).toBe(3n);
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});
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