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Search - "testing randomness"
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Hmm. So have you ever argued in a job interview? Like really standing your ground? In a technical interview?
Today I had a live coding session with a company I'm interested in. The developer was giving me tasks to evolve the feature on and on.
Everything was TDD. Splendid!
However at one point I had to test if the outcome of the method call is random. What I did is basically:
```
Provider<String> provider = new SomeProvider("aaa", "bbb", "ccc", "ddd", "eee", "fff")
for(int i=0; i<100; i++) {
String str = provider.get();
map.put(str, incrementCount(str));
}
Set<Integer> occurences = new HashSet(map.values());
occurences.removeIf(o -> o.equals(occurences.get(0)));
assertFalse(occurences.empty());
```
and I called it good enough, since I cannot verify true randomness.
But the dev argued that this is not enough and I must verify whether the output is truly random or not, and the output (considering the provider only has a finite set of values to return) occurences are almost equal (i.e. the deviation from median is the median itself).
I argued this is not possible and it beats the core principle of randomness -- non-determinism. Since if you can reliably test whether the sequence is truly random you must have an algorithm which determines what value can or cannot be next in the sequence. Which means determinism. And that the (P)RNG is then flawed. The best you can do is to test whether randomness is "good enough" for your use case.
We were arguing and he eventually said "alright, let's call it a good enough solution, since we're short on time".
I wonder whether this will have adverse effect my evaluation . So have you ever argued with your interviewer? Did it turn out to the better or to the worse?
But more importantly, was I right? :D21