stack.go

package stack
import "errors"

type Stack []interface {}
func (stack Stack) Len() int {
    return len(stack)
}
func (stack Stack) IsEmpty() bool  {
    return len(stack) == 0
}
func (stack Stack) Cap() int {
    return cap(stack)
}
func (stack *Stack) Push(value interface{})  {
    *stack = append(*stack, value)
}
func (stack Stack) Top() (interface{}, error)  {
    if len(stack) == 0 {
        return nil, errors.New("Out of index, len is 0")
    }
    return stack[len(stack) - 1], nil
}
func (stack *Stack) Pop() (interface{}, error)  {
    theStack := *stack
    if len(theStack) == 0 {
        return nil, errors.New("Out of index, len is 0")
    }
    value := theStack[len(theStack) - 1]
    *stack = theStack[:len(theStack) - 1]
    return value, nil
}

stack_test.go

package stack

import (
    "testing"
)

func TestStack_Len(t *testing.T) {
    var myStack Stack
    myStack.Push(1)
    myStack.Push("test")
    if myStack.Len() == 2 {
        t.Log("Pass Stack.Len")
    } else {
        t.Error("Failed Stack.Len")
    }
}

func TestStack_IsEmpty(t *testing.T) {
    var mStack Stack
    if mStack.IsEmpty() {
        t.Log("Pass Stack.IsEmpty")
    } else {
        t.Error("Failed Stack.IsEmpty")
    }
}

func TestStack_Cap(t *testing.T) {
    myStack := make(Stack, 3)
    if myStack.Cap() == 3 {
        t.Log("Pass Stack.Cap")
    } else {
        t.Error("Failed Stack.Cap")
    }
}

func TestStack_Push(t *testing.T) {
    var mStack Stack
    mStack.Push(3)
    if mStack.Len() == 1 {
        t.Log("Pass Stack.Push")
    } else {
        t.Error("Failed Stack.Push")
    }
}

func TestStack_Top(t *testing.T) {
    var mStack Stack
    if _, err := mStack.Top(); err == nil {
        t.Error("Failed Stack.Top")
    }
    mStack.Push(3)
    if value, _ := mStack.Top(); value == 3 {
        t.Log("Pass Stack.Top")
    } else {
        t.Errorf("Failed Stack.Top, value is %d", value)
    }
}

func TestStack_Pop(t *testing.T) {
    var mStack Stack
    if _, err := mStack.Pop(); err == nil {
        t.Error("Failed Stack.Top")
    }
    mStack.Push("test")
    mStack.Push(3)
    if value, _ := mStack.Pop(); value == 3 && mStack.Len() == 1 {
        t.Log("Pass Stack.Pop")
    } else {
        t.Errorf("Failed Stack.Pop, value is %d, len is %d", value, mStack.Len())
    }
}