xorshiftr128plus_test.gno

  1package xorshiftr128plus
  2
  3import (
  4	"math/rand"
  5	"testing"
  6)
  7
  8func TestXorshift64StarSeeding(t *testing.T) {
  9	rnd := New()
 10	value1 := rnd.Uint64()
 11
 12	rnd = New(987654321)
 13	value2 := rnd.Uint64()
 14
 15	rnd = New(987654321, 9876543210)
 16	value3 := rnd.Uint64()
 17
 18	if value1 != 4368859828809982745 ||
 19		value2 != 6152356058823566752 ||
 20		value3 != 8285073084540510 ||
 21		value1 == value2 ||
 22		value2 == value3 ||
 23		value1 == value3 {
 24		t.Errorf("Expected three different values\n  got: %d, %d, %d", value1, value2, value3)
 25	}
 26}
 27
 28func TestXorshiftr128PlusRand(t *testing.T) {
 29	rnd := New(987654321)
 30	rng := rand.New(rnd)
 31
 32	// Expected outputs for the first 5 random floats with the given seed
 33	expected := []float64{
 34		0.048735219800779106,
 35		0.0372152171449619,
 36		0.667254760531175,
 37		0.16615979111253953,
 38		0.27578895545492665,
 39		0.48342823127830337,
 40		0.7825693830495895,
 41		0.14643955390763952,
 42		0.29003469381875835,
 43		0.726334398545258,
 44	}
 45
 46	for i, exp := range expected {
 47		val := rng.Float64()
 48		if exp != val {
 49			t.Errorf("Rand.Float64() at iteration %d: got %g, expected %g", i, val, exp)
 50		}
 51	}
 52}
 53
 54func TestXorshiftr128PlusUint64(t *testing.T) {
 55	rnd := New(987654321, 9876543210)
 56
 57	expected := []uint64{
 58		8285073084540510,
 59		97010855169053386,
 60		11353359435625603792,
 61		10289232744262291728,
 62		14019961444418950453,
 63		15829492476941720545,
 64		2764732928842099222,
 65		6871047144273883379,
 66		16142204260470661970,
 67		11803223757041229095,
 68	}
 69
 70	for i, exp := range expected {
 71		val := rnd.Uint64()
 72		if exp != val {
 73			t.Errorf("Xorshiftr128Plus.Uint64() at iteration %d: got %d, expected %d", i, val, exp)
 74		}
 75	}
 76}
 77
 78func TestXorshiftr128PlusMarshalUnmarshal(t *testing.T) {
 79	rnd := New(987654321, 9876543210)
 80
 81	expected1 := []uint64{
 82		8285073084540510,
 83		97010855169053386,
 84		11353359435625603792,
 85		10289232744262291728,
 86		14019961444418950453,
 87	}
 88
 89	expected2 := []uint64{
 90		15829492476941720545,
 91		2764732928842099222,
 92		6871047144273883379,
 93		16142204260470661970,
 94		11803223757041229095,
 95	}
 96
 97	for i, exp := range expected1 {
 98		val := rnd.Uint64()
 99		if exp != val {
100			t.Errorf("Xorshiftr128Plus.Uint64() at iteration %d: got %d, expected %d", i, val, exp)
101		}
102	}
103
104	marshalled, err := rnd.MarshalBinary()
105
106	// t.Logf("Original State: [%x]\n", rnd.seed)
107	// t.Logf("Marshalled State: [%x] -- %v\n", marshalled, err)
108	state_before := rnd.seed
109
110	if err != nil {
111		t.Errorf("Xorshiftr128Plus.MarshalBinary() error: %v", err)
112	}
113
114	// Advance state by one number; then check the next 5. The expectation is that they _will_ fail.
115	rnd.Uint64()
116
117	for i, exp := range expected2 {
118		val := rnd.Uint64()
119		if exp == val {
120			t.Errorf("  Iteration %d matched %d; which is from iteration %d; something strange is happening.", (i + 6), val, (i + 5))
121		}
122	}
123
124	// t.Logf("State before unmarshall: [%x]\n", rnd.seed)
125
126	// Now restore the state of the PRNG
127	err = rnd.UnmarshalBinary(marshalled)
128
129	// t.Logf("State after unmarshall: [%x]\n", rnd.seed)
130
131	if state_before != rnd.seed {
132		t.Errorf("States before and after marshal/unmarshal are not equal; go %x and %x", state_before, rnd.seed)
133	}
134
135	// Now we should be back on track for the last 5 numbers
136	for i, exp := range expected2 {
137		val := rnd.Uint64()
138		if exp != val {
139			t.Errorf("Xorshiftr128Plus.Uint64() at iteration %d: got %d, expected %d", (i + 5), val, exp)
140		}
141	}
142}