feat: add unit test

randomizer/rand.go

@@ -0,0 +1,35 @@
+package randomizer
+
+import "math/rand"
+
+type Random interface {
+	Int() int
+}
+
+func init(){}
+type rndGenerator func(n int) int
+
+type Randomizer struct {
+	fn rndGenerator
+}
+
+func NewRandomizer(fn rndGenerator) *Randomizer {
+	return &Randomizer{fn: fn}
+}
+
+func (r *Randomizer) Int(n int) int {
+	return r.fn(n)
+}
+
+func Rand(rand int) int {
+	return randGen(rand)
+}
+func realRand(n int) int { return int(rand.Intn(n)) }
+func fakeRand(n int) func(_ int) int {
+	return func(_ int)int { return n}
+}
+var randGen = NewRandomizer(realRand).Int
+
+func FakeRandomizer(n int) {
+	randGen = NewRandomizer(fakeRand(n)).Int
+}