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package queue
import (
"testing"
"github.com/stretchr/testify/require"
)
func TestQueueBasic(t *testing.T) {
q := New[string](5)
require.NotNil(t, q)
require.Zero(t, q.Len())
require.Same(t, q.head, q.tail)
require.EqualValues(t, 1, q.head.Len())
v := q.Dequeue()
require.Nil(t, v)
require.Zero(t, q.Len())
require.Same(t, q.head, q.tail)
require.EqualValues(t, 1, q.head.Len())
const one = "one"
q.Enqueue(one)
require.EqualValues(t, 1, q.Len())
require.Same(t, q.head, q.tail)
require.EqualValues(t, 1, q.head.Len())
seg, ok := q.head.Value.(*segment[string])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 1, seg.tail)
v = q.Dequeue()
require.NotNil(t, v)
require.EqualValues(t, one, *v)
require.Zero(t, q.Len())
require.Same(t, q.head, q.tail)
require.EqualValues(t, 1, q.head.Len())
seg, ok = q.head.Value.(*segment[string])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 0, seg.tail)
v = q.Dequeue()
require.Nil(t, v)
require.EqualValues(t, 1, q.head.Len())
const two = "two"
q.Enqueue(one)
q.Enqueue(two)
require.EqualValues(t, 2, q.Len())
require.Same(t, q.head, q.tail)
require.EqualValues(t, 1, q.head.Len())
seg, ok = q.head.Value.(*segment[string])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 2, seg.tail)
v = q.Dequeue()
require.NotNil(t, v)
require.EqualValues(t, one, *v)
require.EqualValues(t, 1, q.head.Len())
seg, ok = q.head.Value.(*segment[string])
require.True(t, ok)
require.EqualValues(t, 1, seg.head)
require.EqualValues(t, 2, seg.tail)
v = q.Dequeue()
require.NotNil(t, v)
require.EqualValues(t, two, *v)
require.EqualValues(t, 1, q.head.Len())
seg, ok = q.head.Value.(*segment[string])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 0, seg.tail)
}
func TestQueueNewSeg(t *testing.T) {
const size = 5
q := New[int](size)
require.NotNil(t, q)
// fill up first segment
for i := 0; i < size; i++ {
q.Enqueue(i + 1)
}
// verify there's no new segment
require.EqualValues(t, size, q.Len())
require.Same(t, q.head, q.tail)
seg, ok := q.head.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, size, seg.tail)
// with first segment full, a new one is created
q.Enqueue(6)
require.EqualValues(t, size+1, q.Len())
require.NotSame(t, q.head, q.tail)
require.EqualValues(t, 2, q.head.Len())
// first segment undisturbed
seg, ok = q.head.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, size, seg.tail)
// second segment contains one item
seg, ok = q.tail.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 1, seg.tail)
// new segment properly linked
require.EqualValues(t, q.tail, q.head.Next())
require.EqualValues(t, q.head, q.tail.Next())
// dequeue the first three items
for i := 0; i < 3; i++ {
val := q.Dequeue()
require.NotNil(t, val)
require.EqualValues(t, i+1, *val)
}
require.EqualValues(t, 3, q.Len())
// should be two items left
seg, ok = q.head.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, size-2, seg.head)
require.EqualValues(t, size, seg.tail)
// enqueue another item
q.Enqueue(7)
require.EqualValues(t, 4, q.Len())
// first segment is undisturbed (still two items)
seg, ok = q.head.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, size-2, seg.head)
require.EqualValues(t, size, seg.tail)
// now there are two items in the second segment
seg, ok = q.tail.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 2, seg.tail)
// now dequeue remaining items in first segment
for i := 0; i < 2; i++ {
val := q.Dequeue()
require.NotNil(t, val)
require.EqualValues(t, i+4, *val)
}
require.EqualValues(t, 2, q.Len())
require.EqualValues(t, 2, q.head.Len())
// first segement is now empty and q.head has advanced
require.Same(t, q.head, q.tail)
seg, ok = q.tail.Prev().Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 0, seg.tail)
// enqueueing another value
q.Enqueue(8)
require.EqualValues(t, 3, q.Len())
require.Same(t, q.head, q.tail)
seg, ok = q.head.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 3, seg.tail)
// should not touch first (empty) segment
seg, ok = q.head.Prev().Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 0, seg.tail)
// dequeue items from second segment (one left)
for i := 0; i < 2; i++ {
val := q.Dequeue()
require.NotNil(t, val)
require.EqualValues(t, 6+i, *val)
}
require.EqualValues(t, 1, q.Len())
seg, ok = q.head.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 2, seg.head)
require.EqualValues(t, 3, seg.tail)
// dequeue last item
val := q.Dequeue()
require.NotNil(t, val)
require.EqualValues(t, 8, *val)
require.Zero(t, q.Len())
require.Same(t, q.head, q.tail)
// both segments are empty
seg, ok = q.head.Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 0, seg.tail)
seg, ok = q.head.Next().Value.(*segment[int])
require.True(t, ok)
require.EqualValues(t, 0, seg.head)
require.EqualValues(t, 0, seg.tail)
require.EqualValues(t, 2, q.head.Len())
}
func TestManyItemsStableRingCount(t *testing.T) {
const (
items = 5000
factor = 10
segSize = items / factor
)
q := New[int](segSize)
for n := 0; n < 100; n++ {
for i := 0; i < items; i++ {
q.Enqueue(i)
if n == 0 && i > 0 && i%segSize == 0 {
// on the first iteration, for every seg-size inserts, we should see a new segment
require.EqualValues(t, (i/segSize)+1, q.head.Len())
}
}
require.EqualValues(t, items, q.Len())
require.EqualValues(t, factor, q.head.Len())
for i := 0; i < items; i++ {
v := q.Dequeue()
require.NotNil(t, v)
require.EqualValues(t, i, *v)
}
require.Zero(t, q.Len())
require.EqualValues(t, factor, q.head.Len())
require.Same(t, q.head, q.tail)
}
}
func TestChasingRingGrowth(t *testing.T) {
const (
items = 5000
factor = 10
segSize = items / factor
)
q := New[int](segSize)
// create two segments
for i := 0; i < segSize*2; i++ {
q.Enqueue(i)
}
require.EqualValues(t, 2, q.head.Len())
require.NotSame(t, q.head, q.tail)
// drain first
for i := 0; i < segSize; i++ {
v := q.Dequeue()
require.NotNil(t, v)
}
require.EqualValues(t, 2, q.head.Len())
require.Same(t, q.head, q.tail)
// old head is reused now
for i := 0; i < segSize; i++ {
q.Enqueue(i)
}
require.EqualValues(t, 2, q.head.Len())
for i := 0; i < segSize; i++ {
v := q.Dequeue()
require.NotNil(t, v)
}
require.EqualValues(t, 2, q.head.Len())
for i := 0; i < segSize; i++ {
v := q.Dequeue()
require.NotNil(t, v)
}
require.EqualValues(t, 2, q.head.Len())
require.Zero(t, q.Len())
require.Same(t, q.head, q.tail)
// two segments now, add a third
for i := 0; i < segSize*3; i++ {
q.Enqueue(i)
}
require.EqualValues(t, 3, q.head.Len())
require.NotSame(t, q.head, q.tail)
// drain first two
for i := 0; i < segSize*2; i++ {
v := q.Dequeue()
require.NotNil(t, v)
}
require.EqualValues(t, 3, q.head.Len())
require.Same(t, q.head, q.tail)
// fill up one
for i := 0; i < segSize; i++ {
q.Enqueue(i)
}
require.EqualValues(t, 3, q.head.Len())
require.NotSame(t, q.head, q.tail)
require.EqualValues(t, segSize*2, q.Len())
// drain all
for {
v := q.Dequeue()
if v == nil {
break
}
}
require.EqualValues(t, 3, q.head.Len())
require.Same(t, q.head, q.tail)
require.Zero(t, q.Len())
}
|
