gds/stack_test.go at main · renaldid/gds · GitHub

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package gds

import (
	"testing"

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

func TestStack_Empty(t *testing.T) {
	s := NewStack[int]()
	assert.Equal(t, 0, s.Len())
	assert.True(t, s.IsEmpty())
}

func TestStack_Push_And_Pop(t *testing.T) {
	s := NewStack[int]()
	s.Push(1, 2, 3)
	v, ok := s.Pop()
	assert.True(t, ok)
	assert.Equal(t, 3, v)
	assert.Equal(t, 2, s.Len())
}

func TestStack_Pop_Empty(t *testing.T) {
	s := NewStack[int]()
	v, ok := s.Pop()
	assert.False(t, ok)
	assert.Zero(t, v)
}

func TestStack_Peek(t *testing.T) {
	s := NewStack[string]()
	s.Push("a", "b")
	v, ok := s.Peek()
	assert.True(t, ok)
	assert.Equal(t, "b", v)
	assert.Equal(t, 2, s.Len()) // not removed
}

func TestStack_Peek_Empty(t *testing.T) {
	s := NewStack[string]()
	v, ok := s.Peek()
	assert.False(t, ok)
	assert.Empty(t, v)
}

func TestStack_LIFO_Order(t *testing.T) {
	s := NewStack[int]()
	s.Push(1, 2, 3)
	var got []int
	for !s.IsEmpty() {
		v, _ := s.Pop()
		got = append(got, v)
	}
	assert.Equal(t, []int{3, 2, 1}, got)
}

func TestStack_Clear(t *testing.T) {
	s := NewStack[int]()
	s.Push(1, 2, 3)
	s.Clear()
	assert.True(t, s.IsEmpty())
	assert.Equal(t, 0, s.Len())
}