Extended test for Random.sample to cover both branches (#715)

I've verified that this test fails without the fix in change
186a8c7c13.

See issue #713
This commit is contained in:
Thorbjørn Lindeijer
2020-07-15 05:15:12 +02:00
committed by GitHub
parent 54b4c233b9
commit f81cb5d23c

View File

@ -6,15 +6,22 @@ var random = Random.new(12345)
System.print(random.sample(["single"])) // expect: single
// Should choose all elements with roughly equal probability.
var list = ["a", "b", "c", "d", "e"]
var histogram = {"a": 0, "b": 0, "c": 0, "d": 0, "e": 0}
for (i in 1..1000) {
var sample = random.sample(list)
histogram[sample] = histogram[sample] + 1
var testProbability = Fn.new { |list|
var histogram = {}
for (entry in list) histogram[entry] = 0
for (i in 1..1000) {
var sample = random.sample(list)
histogram[sample] = histogram[sample] + 1
}
System.print(histogram.count)
for (key in histogram.keys) {
var error = (histogram[key] / (1000 / list.count) - 1).abs
if (error > 0.2) System.print("!!! %(error)")
}
}
System.print(histogram.count) // expect: 5
for (key in histogram.keys) {
var error = (histogram[key] / (1000 / list.count) - 1).abs
if (error > 0.2) System.print("!!! %(error)")
}
// Depending on the size of the list a different algorithm is used, so test both branches.
testProbability.call(["a", "b", "c", "d", "e"]) // expect: 5
testProbability.call([0, 1, 2, 3, 4, 5, 6]) // expect: 7