rand_test.go

package gofn

import (
	"math/rand"
	"testing"

	"github.com/stretchr/testify/assert"
)

func Test_RandChoice(t *testing.T) {
	// Empty input
	v1, b1 := RandChoice[int]()
	assert.Equal(t, 0, v1)
	assert.False(t, b1)
	// One item input
	v2, b2 := RandChoice[float32](1.1)
	assert.Equal(t, float32(1.1), v2)
	assert.True(t, b2)
	// Multiple items input
	v3, b3 := RandChoice[string]("1", "2", "3")
	assert.True(t, Contain([]string{"1", "2", "3"}, v3))
	assert.True(t, b3)
}

func Test_RandChoiceMaker_Next(t *testing.T) {
	// Empty input
	maker1 := NewRandChoiceMaker[int]([]int(nil))
	assert.False(t, maker1.HasNext())
	v1, b1 := maker1.Next()
	assert.Equal(t, 0, v1)
	assert.False(t, b1)

	// One item input
	maker2 := NewRandChoiceMaker([]float32{1.1})
	assert.True(t, maker2.HasNext())
	v2, b2 := maker2.Next()
	assert.False(t, maker2.HasNext())
	assert.Equal(t, float32(1.1), v2)
	assert.True(t, b2)

	// Multiple items input (with using custom rand function)
	maker3 := NewRandChoiceMaker([]string{"1", "2", "3"}, rand.Intn)
	assert.True(t, maker3.HasNext())
	v30, b30 := maker3.Next()
	v31, b31 := maker3.Next()
	v32, b32 := maker3.Next()
	assert.False(t, maker3.HasNext())
	v33, b33 := maker3.Next()
	v34, b34 := maker3.Next()
	assert.True(t, b30 && b31 && b32)
	assert.False(t, b33 || b34)
	v3 := []string{v30, v31, v32, v33, v34}
	Sort(v3)
	assert.Equal(t, []string{"", "", "1", "2", "3"}, v3)
}