161 lines
3.6 KiB
Go
161 lines
3.6 KiB
Go
package stack
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import (
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"fmt"
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"math/big"
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestStackPushPop(t *testing.T) {
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// Create two stack Integers
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a, err := NewInt(big.NewInt(10))
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if err != nil {
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t.Fail()
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}
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b, err := NewInt(big.NewInt(20))
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if err != nil {
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t.Fail()
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}
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// Create a new stack
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testStack := New()
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// Push to stack
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testStack.Push(a).Push(b)
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// There should only be two values on the stack
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assert.Equal(t, 2, testStack.Len())
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// Pop first element and it should be equal to b
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stackElement, err := testStack.Pop()
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if err != nil {
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t.Fail()
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}
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item, err := stackElement.Integer()
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if err != nil {
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t.Fail()
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}
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assert.Equal(t, true, item.Equal(b))
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// Pop second element and it should be equal to a
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stackElement, err = testStack.Pop()
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if err != nil {
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t.Fail()
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}
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item, err = stackElement.Integer()
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if err != nil {
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t.Fail()
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}
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assert.Equal(t, true, item.Equal(a))
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// We should get an error as there are nomore items left to pop
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stackElement, err = testStack.Pop()
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assert.NotNil(t, err)
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}
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// For this test to pass, we should get an error when popping from a nil stack
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// and we should initialise and push an element if pushing to an empty stack
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func TestPushPopNil(t *testing.T) {
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// stack is nil when initialised without New constructor
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testStack := RandomAccess{}
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// Popping from nil stack
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// - should give an error
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// - element returned should be nil
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stackElement, err := testStack.Pop()
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assert.NotNil(t, err)
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assert.Nil(t, stackElement)
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// stack should still be nil after failing to pop
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assert.Nil(t, testStack.vals)
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// create a random test stack item
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a, err := NewInt(big.NewInt(2))
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assert.Nil(t, err)
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// push random item to stack
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testStack.Push(a)
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// push should initialise the stack and put one element on the stack
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assert.Equal(t, 1, testStack.Len())
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}
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// Test passes if we can peek and modify an item
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//without modifying the value on the stack
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func TestStackPeekMutability(t *testing.T) {
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testStack := New()
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a, err := NewInt(big.NewInt(2))
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assert.Nil(t, err)
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b, err := NewInt(big.NewInt(3))
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assert.Nil(t, err)
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testStack.Push(a).Push(b)
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peekedItem := testPeakInteger(t, testStack, 0)
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assert.Equal(t, true, peekedItem.Equal(b))
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// Check that by modifying the peeked value,
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// we did not modify the item on the stack
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peekedItem = a
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peekedItem.val = big.NewInt(0)
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// Pop item from stack and check it is still the same
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poppedItem := testPopInteger(t, testStack)
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assert.Equal(t, true, poppedItem.Equal(b))
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}
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func TestStackPeek(t *testing.T) {
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testStack := New()
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values := []int64{23, 45, 67, 89, 12, 344}
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for _, val := range values {
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a := testMakeStackInt(t, val)
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testStack.Push(a)
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}
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// i starts at 0, j starts at len(values)-1
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for i, j := 0, len(values)-1; j >= 0; i, j = i+1, j-1 {
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peekedItem := testPeakInteger(t, testStack, uint16(i))
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a := testMakeStackInt(t, values[j])
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fmt.Printf("%#v\n", peekedItem.val.Int64())
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assert.Equal(t, true, a.Equal(peekedItem))
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}
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}
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func TestStackInsert(t *testing.T) {
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testStack := New()
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a := testMakeStackInt(t, 2)
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b := testMakeStackInt(t, 4)
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c := testMakeStackInt(t, 6)
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// insert on an empty stack should put element on top
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_, err := testStack.Insert(0, a)
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assert.Equal(t, err, nil)
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_, err = testStack.Insert(0, b)
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assert.Equal(t, err, nil)
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_, err = testStack.Insert(1, c)
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assert.Equal(t, err, nil)
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// Order should be [a,c,b]
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pop1 := testPopInteger(t, testStack)
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pop2 := testPopInteger(t, testStack)
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pop3 := testPopInteger(t, testStack)
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assert.Equal(t, true, pop1.Equal(b))
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assert.Equal(t, true, pop2.Equal(c))
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assert.Equal(t, true, pop3.Equal(a))
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}
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