0xff, 0xff, 0xff, 0x20, 0x00,
	}
	defer func() {
		if r := recover(); r != nil {
			t.Fatalf("NewReader panicked: %s", r)
		}
	}()
	// Previously, this would trigger a panic as we attempt to read from
	// an io.SectionReader which would access a slice at a negative offset
	// as the section reader offset & size were < 0.
	NewReader(bytes.NewReader(data), int64(len(data))+1875)

		},
	}, {
		maker: makeReg{"hello, world", 50},
		tests: []testFnc{
			testRemaining{50, 50},
			testRead{7, "hello, ", nil},
			testRemaining{43, 43},
			testRead{5, "world", nil},
			testRemaining{38, 38},
			testWriteTo{nil, 0, io.ErrUnexpectedEOF},
			testRead{1, "", io.ErrUnexpectedEOF},
			testRemaining{38, 38},
		},
	}, {
		maker: makeReg{"hello, world", 5},
		tests: []testFnc{

			t.Errorf("got string %q; want %q", b.String(), s)
		}
		if r.Len() != 0 {
			t.Errorf("reader contains %v bytes; want 0", r.Len())
		}
	}
}

func TestReaderLen(t *testing.T) {
	const data = "hello world"
	r := NewReader([]byte(data))
	if got, want := r.Len(), 11; got != want {
		t.Errorf("r.Len(): got %d, want %d", got, want)
	}
	if n, err := r.Read(make([]byte, 10)); err != nil || n != 10 {