}
		// multiplication is commutative
		d, ok2 := int64Multiply(test.b, test.a)
		if c != d || ok != ok2 {
			t.Errorf("%v: not commutative: %d %t", test, d, ok2)
		}
	}
}

func TestDetectOverflowScale(t *testing.T) {
	for _, a := range []int64{0, -1, 1, 10, -10, mostPositive, mostNegative, -mostPositive} {
		for _, b := range []int64{1, 2, 10, 100, 1000, mostPositive} {
			expect, expectOk := int64Multiply(a, b)