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Source file src/container/list/list_test.go

Documentation: container/list

  // Copyright 2009 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package list
  
  import "testing"
  
  func checkListLen(t *testing.T, l *List, len int) bool {
  	if n := l.Len(); n != len {
  		t.Errorf("l.Len() = %d, want %d", n, len)
  		return false
  	}
  	return true
  }
  
  func checkListPointers(t *testing.T, l *List, es []*Element) {
  	root := &l.root
  
  	if !checkListLen(t, l, len(es)) {
  		return
  	}
  
  	// zero length lists must be the zero value or properly initialized (sentinel circle)
  	if len(es) == 0 {
  		if l.root.next != nil && l.root.next != root || l.root.prev != nil && l.root.prev != root {
  			t.Errorf("l.root.next = %p, l.root.prev = %p; both should both be nil or %p", l.root.next, l.root.prev, root)
  		}
  		return
  	}
  	// len(es) > 0
  
  	// check internal and external prev/next connections
  	for i, e := range es {
  		prev := root
  		Prev := (*Element)(nil)
  		if i > 0 {
  			prev = es[i-1]
  			Prev = prev
  		}
  		if p := e.prev; p != prev {
  			t.Errorf("elt[%d](%p).prev = %p, want %p", i, e, p, prev)
  		}
  		if p := e.Prev(); p != Prev {
  			t.Errorf("elt[%d](%p).Prev() = %p, want %p", i, e, p, Prev)
  		}
  
  		next := root
  		Next := (*Element)(nil)
  		if i < len(es)-1 {
  			next = es[i+1]
  			Next = next
  		}
  		if n := e.next; n != next {
  			t.Errorf("elt[%d](%p).next = %p, want %p", i, e, n, next)
  		}
  		if n := e.Next(); n != Next {
  			t.Errorf("elt[%d](%p).Next() = %p, want %p", i, e, n, Next)
  		}
  	}
  }
  
  func TestList(t *testing.T) {
  	l := New()
  	checkListPointers(t, l, []*Element{})
  
  	// Single element list
  	e := l.PushFront("a")
  	checkListPointers(t, l, []*Element{e})
  	l.MoveToFront(e)
  	checkListPointers(t, l, []*Element{e})
  	l.MoveToBack(e)
  	checkListPointers(t, l, []*Element{e})
  	l.Remove(e)
  	checkListPointers(t, l, []*Element{})
  
  	// Bigger list
  	e2 := l.PushFront(2)
  	e1 := l.PushFront(1)
  	e3 := l.PushBack(3)
  	e4 := l.PushBack("banana")
  	checkListPointers(t, l, []*Element{e1, e2, e3, e4})
  
  	l.Remove(e2)
  	checkListPointers(t, l, []*Element{e1, e3, e4})
  
  	l.MoveToFront(e3) // move from middle
  	checkListPointers(t, l, []*Element{e3, e1, e4})
  
  	l.MoveToFront(e1)
  	l.MoveToBack(e3) // move from middle
  	checkListPointers(t, l, []*Element{e1, e4, e3})
  
  	l.MoveToFront(e3) // move from back
  	checkListPointers(t, l, []*Element{e3, e1, e4})
  	l.MoveToFront(e3) // should be no-op
  	checkListPointers(t, l, []*Element{e3, e1, e4})
  
  	l.MoveToBack(e3) // move from front
  	checkListPointers(t, l, []*Element{e1, e4, e3})
  	l.MoveToBack(e3) // should be no-op
  	checkListPointers(t, l, []*Element{e1, e4, e3})
  
  	e2 = l.InsertBefore(2, e1) // insert before front
  	checkListPointers(t, l, []*Element{e2, e1, e4, e3})
  	l.Remove(e2)
  	e2 = l.InsertBefore(2, e4) // insert before middle
  	checkListPointers(t, l, []*Element{e1, e2, e4, e3})
  	l.Remove(e2)
  	e2 = l.InsertBefore(2, e3) // insert before back
  	checkListPointers(t, l, []*Element{e1, e4, e2, e3})
  	l.Remove(e2)
  
  	e2 = l.InsertAfter(2, e1) // insert after front
  	checkListPointers(t, l, []*Element{e1, e2, e4, e3})
  	l.Remove(e2)
  	e2 = l.InsertAfter(2, e4) // insert after middle
  	checkListPointers(t, l, []*Element{e1, e4, e2, e3})
  	l.Remove(e2)
  	e2 = l.InsertAfter(2, e3) // insert after back
  	checkListPointers(t, l, []*Element{e1, e4, e3, e2})
  	l.Remove(e2)
  
  	// Check standard iteration.
  	sum := 0
  	for e := l.Front(); e != nil; e = e.Next() {
  		if i, ok := e.Value.(int); ok {
  			sum += i
  		}
  	}
  	if sum != 4 {
  		t.Errorf("sum over l = %d, want 4", sum)
  	}
  
  	// Clear all elements by iterating
  	var next *Element
  	for e := l.Front(); e != nil; e = next {
  		next = e.Next()
  		l.Remove(e)
  	}
  	checkListPointers(t, l, []*Element{})
  }
  
  func checkList(t *testing.T, l *List, es []interface{}) {
  	if !checkListLen(t, l, len(es)) {
  		return
  	}
  
  	i := 0
  	for e := l.Front(); e != nil; e = e.Next() {
  		le := e.Value.(int)
  		if le != es[i] {
  			t.Errorf("elt[%d].Value = %v, want %v", i, le, es[i])
  		}
  		i++
  	}
  }
  
  func TestExtending(t *testing.T) {
  	l1 := New()
  	l2 := New()
  
  	l1.PushBack(1)
  	l1.PushBack(2)
  	l1.PushBack(3)
  
  	l2.PushBack(4)
  	l2.PushBack(5)
  
  	l3 := New()
  	l3.PushBackList(l1)
  	checkList(t, l3, []interface{}{1, 2, 3})
  	l3.PushBackList(l2)
  	checkList(t, l3, []interface{}{1, 2, 3, 4, 5})
  
  	l3 = New()
  	l3.PushFrontList(l2)
  	checkList(t, l3, []interface{}{4, 5})
  	l3.PushFrontList(l1)
  	checkList(t, l3, []interface{}{1, 2, 3, 4, 5})
  
  	checkList(t, l1, []interface{}{1, 2, 3})
  	checkList(t, l2, []interface{}{4, 5})
  
  	l3 = New()
  	l3.PushBackList(l1)
  	checkList(t, l3, []interface{}{1, 2, 3})
  	l3.PushBackList(l3)
  	checkList(t, l3, []interface{}{1, 2, 3, 1, 2, 3})
  
  	l3 = New()
  	l3.PushFrontList(l1)
  	checkList(t, l3, []interface{}{1, 2, 3})
  	l3.PushFrontList(l3)
  	checkList(t, l3, []interface{}{1, 2, 3, 1, 2, 3})
  
  	l3 = New()
  	l1.PushBackList(l3)
  	checkList(t, l1, []interface{}{1, 2, 3})
  	l1.PushFrontList(l3)
  	checkList(t, l1, []interface{}{1, 2, 3})
  }
  
  func TestRemove(t *testing.T) {
  	l := New()
  	e1 := l.PushBack(1)
  	e2 := l.PushBack(2)
  	checkListPointers(t, l, []*Element{e1, e2})
  	e := l.Front()
  	l.Remove(e)
  	checkListPointers(t, l, []*Element{e2})
  	l.Remove(e)
  	checkListPointers(t, l, []*Element{e2})
  }
  
  func TestIssue4103(t *testing.T) {
  	l1 := New()
  	l1.PushBack(1)
  	l1.PushBack(2)
  
  	l2 := New()
  	l2.PushBack(3)
  	l2.PushBack(4)
  
  	e := l1.Front()
  	l2.Remove(e) // l2 should not change because e is not an element of l2
  	if n := l2.Len(); n != 2 {
  		t.Errorf("l2.Len() = %d, want 2", n)
  	}
  
  	l1.InsertBefore(8, e)
  	if n := l1.Len(); n != 3 {
  		t.Errorf("l1.Len() = %d, want 3", n)
  	}
  }
  
  func TestIssue6349(t *testing.T) {
  	l := New()
  	l.PushBack(1)
  	l.PushBack(2)
  
  	e := l.Front()
  	l.Remove(e)
  	if e.Value != 1 {
  		t.Errorf("e.value = %d, want 1", e.Value)
  	}
  	if e.Next() != nil {
  		t.Errorf("e.Next() != nil")
  	}
  	if e.Prev() != nil {
  		t.Errorf("e.Prev() != nil")
  	}
  }
  
  func TestMove(t *testing.T) {
  	l := New()
  	e1 := l.PushBack(1)
  	e2 := l.PushBack(2)
  	e3 := l.PushBack(3)
  	e4 := l.PushBack(4)
  
  	l.MoveAfter(e3, e3)
  	checkListPointers(t, l, []*Element{e1, e2, e3, e4})
  	l.MoveBefore(e2, e2)
  	checkListPointers(t, l, []*Element{e1, e2, e3, e4})
  
  	l.MoveAfter(e3, e2)
  	checkListPointers(t, l, []*Element{e1, e2, e3, e4})
  	l.MoveBefore(e2, e3)
  	checkListPointers(t, l, []*Element{e1, e2, e3, e4})
  
  	l.MoveBefore(e2, e4)
  	checkListPointers(t, l, []*Element{e1, e3, e2, e4})
  	e2, e3 = e3, e2
  
  	l.MoveBefore(e4, e1)
  	checkListPointers(t, l, []*Element{e4, e1, e2, e3})
  	e1, e2, e3, e4 = e4, e1, e2, e3
  
  	l.MoveAfter(e4, e1)
  	checkListPointers(t, l, []*Element{e1, e4, e2, e3})
  	e2, e3, e4 = e4, e2, e3
  
  	l.MoveAfter(e2, e3)
  	checkListPointers(t, l, []*Element{e1, e3, e2, e4})
  	e2, e3 = e3, e2
  }
  
  // Test PushFront, PushBack, PushFrontList, PushBackList with uninitialized List
  func TestZeroList(t *testing.T) {
  	var l1 = new(List)
  	l1.PushFront(1)
  	checkList(t, l1, []interface{}{1})
  
  	var l2 = new(List)
  	l2.PushBack(1)
  	checkList(t, l2, []interface{}{1})
  
  	var l3 = new(List)
  	l3.PushFrontList(l1)
  	checkList(t, l3, []interface{}{1})
  
  	var l4 = new(List)
  	l4.PushBackList(l2)
  	checkList(t, l4, []interface{}{1})
  }
  
  // Test that a list l is not modified when calling InsertBefore with a mark that is not an element of l.
  func TestInsertBeforeUnknownMark(t *testing.T) {
  	var l List
  	l.PushBack(1)
  	l.PushBack(2)
  	l.PushBack(3)
  	l.InsertBefore(1, new(Element))
  	checkList(t, &l, []interface{}{1, 2, 3})
  }
  
  // Test that a list l is not modified when calling InsertAfter with a mark that is not an element of l.
  func TestInsertAfterUnknownMark(t *testing.T) {
  	var l List
  	l.PushBack(1)
  	l.PushBack(2)
  	l.PushBack(3)
  	l.InsertAfter(1, new(Element))
  	checkList(t, &l, []interface{}{1, 2, 3})
  }
  
  // Test that a list l is not modified when calling MoveAfter or MoveBefore with a mark that is not an element of l.
  func TestMoveUnknownMark(t *testing.T) {
  	var l1 List
  	e1 := l1.PushBack(1)
  
  	var l2 List
  	e2 := l2.PushBack(2)
  
  	l1.MoveAfter(e1, e2)
  	checkList(t, &l1, []interface{}{1})
  	checkList(t, &l2, []interface{}{2})
  
  	l1.MoveBefore(e1, e2)
  	checkList(t, &l1, []interface{}{1})
  	checkList(t, &l2, []interface{}{2})
  }
  

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