package logbuf

import (
	"strings"
	"sync"
	"testing"
)

func TestBufferConcurrentWriteAndCap(t *testing.T) {
	b := New(64)
	var wg sync.WaitGroup
	for i := 0; i < 8; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			for j := 0; j < 40; j++ {
				_, _ = b.Write([]byte("abcdefghij"))
			}
		}()
	}
	wg.Wait()
	if b.Len() > 64+40 { // allow truncate marker overhead
		t.Fatalf("len=%d exceeds soft cap", b.Len())
	}
	s := b.String()
	if !strings.Contains(s, "abcdefghij") && !strings.Contains(s, "truncated") {
		t.Fatalf("unexpected content %q", s)
	}
}