1package workerpool
  2
  3import (
  4	"context"
  5	"errors"
  6	"sync/atomic"
  7	"testing"
  8	"time"
  9)
 10
 11func TestPool_Run(t *testing.T) {
 12	pool := New(2)
 13
 14	var count atomic.Int32
 15	tasks := make([]Task, 10)
 16	for i := range tasks {
 17		tasks[i] = func(ctx context.Context) error {
 18			count.Add(1)
 19			return nil
 20		}
 21	}
 22
 23	results := pool.Run(context.Background(), tasks)
 24
 25	if len(results) != 10 {
 26		t.Errorf("expected 10 results, got %d", len(results))
 27	}
 28	if count.Load() != 10 {
 29		t.Errorf("expected 10 task executions, got %d", count.Load())
 30	}
 31	for i, r := range results {
 32		if r.Error != nil {
 33			t.Errorf("task %d unexpected error: %v", i, r.Error)
 34		}
 35	}
 36}
 37
 38func TestPool_RunWithErrors(t *testing.T) {
 39	pool := New(2)
 40
 41	testErr := errors.New("test error")
 42	tasks := []Task{
 43		func(ctx context.Context) error { return nil },
 44		func(ctx context.Context) error { return testErr },
 45		func(ctx context.Context) error { return nil },
 46	}
 47
 48	results := pool.Run(context.Background(), tasks)
 49
 50	if results[0].Error != nil {
 51		t.Error("task 0 should succeed")
 52	}
 53	if !errors.Is(results[1].Error, testErr) {
 54		t.Errorf("task 1 expected testErr, got %v", results[1].Error)
 55	}
 56	if results[2].Error != nil {
 57		t.Error("task 2 should succeed")
 58	}
 59}
 60
 61func TestPool_ContextCancellation(t *testing.T) {
 62	pool := New(1)
 63
 64	ctx, cancel := context.WithCancel(context.Background())
 65
 66	started := make(chan struct{})
 67	tasks := []Task{
 68		func(ctx context.Context) error {
 69			close(started)
 70			time.Sleep(100 * time.Millisecond)
 71			return nil
 72		},
 73		func(ctx context.Context) error {
 74			return nil
 75		},
 76	}
 77
 78	go func() {
 79		<-started
 80		cancel()
 81	}()
 82
 83	results := pool.Run(ctx, tasks)
 84
 85	// At least one task should have context error
 86	hasCtxErr := false
 87	for _, r := range results {
 88		if errors.Is(r.Error, context.Canceled) {
 89			hasCtxErr = true
 90			break
 91		}
 92	}
 93	if !hasCtxErr {
 94		// May complete before cancellation - that's OK
 95		t.Log("all tasks completed before cancellation")
 96	}
 97}
 98
 99func TestPool_EmptyTasks(t *testing.T) {
100	pool := New(4)
101	results := pool.Run(context.Background(), nil)
102
103	if len(results) != 0 {
104		t.Errorf("expected 0 results, got %d", len(results))
105	}
106}