func (rbs *readBadSeeker) Seek(int64, int) (int64, error) { return 0, fmt.Errorf("illegal seek") }

// TestReadTruncation tests the ending condition on various truncated files and
// that truncated files are still detected even if the underlying io.Reader
// satisfies io.Seeker.
func TestReadTruncation(t *testing.T) {
	var ss []string
	for _, p := range []string{
		"testdata/gnu.tar",
		"testdata/ustar-file-reg.tar",