github.com/grailbio/base@v0.0.11/syncqueue/syncqueue_test.go (about)

     1  // Copyright 2018 GRAIL, Inc. All rights reserved.
     2  // Use of this source code is governed by the Apache-2.0
     3  // license that can be found in the LICENSE file.
     4  
     5  package syncqueue_test
     6  
     7  import (
     8  	"fmt"
     9  	"testing"
    10  
    11  	"github.com/grailbio/base/syncqueue"
    12  	"github.com/stretchr/testify/require"
    13  )
    14  
    15  func ExampleLIFO() {
    16  	q := syncqueue.NewLIFO()
    17  	q.Put("item0")
    18  	q.Put("item1")
    19  	q.Close()
    20  	v0, ok := q.Get()
    21  	fmt.Println("Item 0:", v0.(string), ok)
    22  	v1, ok := q.Get()
    23  	fmt.Println("Item 1:", v1.(string), ok)
    24  	v2, ok := q.Get()
    25  	fmt.Println("Item 2:", v2, ok)
    26  	// Output:
    27  	// Item 0: item1 true
    28  	// Item 1: item0 true
    29  	// Item 2: <nil> false
    30  }
    31  
    32  func TestLIFOWithThreads(t *testing.T) {
    33  	q := syncqueue.NewLIFO()
    34  	ch := make(chan string, 3)
    35  
    36  	// Check if "ch" has any data.
    37  	chanEmpty := func() bool {
    38  		select {
    39  		case <-ch:
    40  			return false
    41  		default:
    42  			return true
    43  		}
    44  	}
    45  
    46  	go func() {
    47  		for {
    48  			val, ok := q.Get()
    49  			if !ok {
    50  				break
    51  			}
    52  			ch <- val.(string)
    53  		}
    54  	}()
    55  	s := []string{}
    56  	q.Put("item0")
    57  	q.Put("item1")
    58  	s = append(s, <-ch, <-ch)
    59  	require.True(t, chanEmpty())
    60  
    61  	q.Put("item2")
    62  	s = append(s, <-ch)
    63  	require.True(t, chanEmpty())
    64  
    65  	require.Equal(t, []string{"item1", "item0", "item2"}, s)
    66  }