package logging

import (
	"bytes"
	"errors"
	"testing"

	"github.com/stretchr/testify/require"
)

type WriteErrorBuffer struct{}

func (*WriteErrorBuffer) Write(_ []byte) (int, error) {
	return 0, errors.New("cannot write")
}

func TestFileBackendWrite(t *testing.T) {
	t.Parallel()

	t.Run("It should write the logs to the buffer", func(t *testing.T) {
		t.Parallel()

		buf := new(bytes.Buffer)
		b := NewIoBackend(buf)

		err := b.Write(&Record{
			Level:   Info,
			Message: "my log line",
		})

		require.NoError(t, err)
		require.Contains(t, buf.String(), "my log line")
	})

	t.Run("It should return an error if it cannot write the log", func(t *testing.T) {
		t.Parallel()

		buf := new(WriteErrorBuffer)
		b := NewIoBackend(buf)

		err := b.Write(&Record{
			Level:   Info,
			Message: "my log line",
		})

		require.Error(t, err)
	})
}