v8/test/cctest/test-random-number-generator.cc

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#include "src/v8.h"
#include "test/cctest/cctest.h"

#include "src/isolate-inl.h"
#include "src/utils/random-number-generator.h"

using namespace v8::internal;


static const int kMaxRuns = 12345;
static const int kRandomSeeds[] = {
  -1, 1, 42, 100, 1234567890, 987654321
};


TEST(NextIntWithMaxValue) {
  for (unsigned n = 0; n < ARRAY_SIZE(kRandomSeeds); ++n) {
    RandomNumberGenerator rng(kRandomSeeds[n]);
    for (int max = 1; max <= kMaxRuns; ++max) {
      int n = rng.NextInt(max);
      CHECK_LE(0, n);
      CHECK_LT(n, max);
    }
  }
}


TEST(NextBoolReturnsBooleanValue) {
  for (unsigned n = 0; n < ARRAY_SIZE(kRandomSeeds); ++n) {
    RandomNumberGenerator rng(kRandomSeeds[n]);
    for (int k = 0; k < kMaxRuns; ++k) {
      bool b = rng.NextBool();
      CHECK(b == false || b == true);
    }
  }
}


TEST(NextDoubleRange) {
  for (unsigned n = 0; n < ARRAY_SIZE(kRandomSeeds); ++n) {
    RandomNumberGenerator rng(kRandomSeeds[n]);
    for (int k = 0; k < kMaxRuns; ++k) {
      double d = rng.NextDouble();
      CHECK_LE(0.0, d);
      CHECK_LT(d, 1.0);
    }
  }
}


TEST(RandomSeedFlagIsUsed) {
  for (unsigned n = 0; n < ARRAY_SIZE(kRandomSeeds); ++n) {
    FLAG_random_seed = kRandomSeeds[n];
    v8::Isolate* i = v8::Isolate::New();
    RandomNumberGenerator& rng1 =
        *reinterpret_cast<Isolate*>(i)->random_number_generator();
    RandomNumberGenerator rng2(kRandomSeeds[n]);
    for (int k = 1; k <= kMaxRuns; ++k) {
      int64_t i1, i2;
      rng1.NextBytes(&i1, sizeof(i1));
      rng2.NextBytes(&i2, sizeof(i2));
      CHECK_EQ(i2, i1);
      CHECK_EQ(rng2.NextInt(), rng1.NextInt());
      CHECK_EQ(rng2.NextInt(k), rng1.NextInt(k));
      CHECK_EQ(rng2.NextDouble(), rng1.NextDouble());
    }
    i->Dispose();
  }
}