list_test.go

package ps

import "testing"

func TestListImmutable(t *testing.T) {
    // build some lists
    one := NewList().Cons("first")
    two := one.Cons("second")
    zwei := one.Cons("zweite")

    // check each list's length
    if size := one.Size(); size != 1 {
        t.Errorf("one doesn't have 1 item, it has %d", size)
    }
    if size := two.Size(); size != 2 {
        t.Errorf("two doesn't have 2 items, it has %d", size)
    }
    if size := zwei.Size(); size != 2 {
        t.Errorf("zwei doesn't have 2 item, it has %d", size)
    }

    // check each list's contents
    if one.Head() != "first" {
        t.Errorf("one has the wrong head")
    }
    if two.Head() != "second" {
        t.Errorf("two has the wrong head")
    }
    if two.Tail().Head() != "first" {
        t.Errorf("two has the wrong ending")
    }
    if zwei.Head() != "zweite" {
        t.Errorf("zwei has the wrong head")
    }
    if zwei.Tail().Head() != "first" {
        t.Errorf("zwei has the wrong ending")
    }
}

// benchmark making a really long list
func BenchmarkListCons(b *testing.B) {
    l := NewList()
    for i := 0; i < b.N; i++ {
        l = l.Cons(i)
    }
}