package binlog

import (
	"strings"
	"testing"
)

func TestFormatBodyPreview(t *testing.T) {
	if got := formatBodyPreview(nil, 256); got != "len=0" {
		t.Fatalf("unexpected empty preview: %q", got)
	}

	small := []byte{0x01, 0x02, 0xAB}
	got := formatBodyPreview(small, 8)
	if !strings.Contains(got, "len=3") || !strings.Contains(got, "0102ab") {
		t.Fatalf("unexpected preview for small body: %q", got)
	}
	if strings.Contains(got, "...") {
		t.Fatalf("small body should not be truncated: %q", got)
	}

	large := make([]byte, 300)
	for i := range large {
		large[i] = byte(i)
	}
	got = formatBodyPreview(large, 16)
	if !strings.Contains(got, "len=300") || !strings.Contains(got, "preview(hex,16B)=") {
		t.Fatalf("unexpected preview for large body: %q", got)
	}
	if !strings.HasSuffix(got, "...") {
		t.Fatalf("large body should be truncated with ellipsis: %q", got)
	}
}