var with, withOut nErr
	with.n, with.err = io.Copy(discard, NewReader(nil))
	withOut.n, withOut.err = io.Copy(discard, justReader{NewReader(nil)})
	if with != withOut {
		t.Errorf("behavior differs: with = %#v; without: %#v", with, withOut)
	}
}

// tests that Len is affected by reads, but Size is not.
func TestReaderLenSize(t *testing.T) {
	r := NewReader([]byte("abc"))
	io.CopyN(io.Discard, r, 1)
	if r.Len() != 2 {

		t.Fatal(err)
	}
	for _, file := range files {
		t.Run(file.Name(), func(t *testing.T) {
			f, err := os.Open(filepath.Join("testdata", file.Name()))
			if err != nil {
				t.Fatal(err)
			}
			r := NewReader(f, &ReaderArgs{})
			var record sql.Record
			for {
				record, err = r.Read(record)
				if err != nil {
					break
				}
			}
			r.Close()
			if err != io.EOF {