assertThrows(EOFException.class, () -> {
            ASN1Util.readTagNumber(s, 0x1F);
        });
    }

    // --- readLength ---

    @Test
    void testReadLength_ShortForm() throws IOException {
        // Definite-length short form (length 10)
        InputStream s = new ByteArrayInputStream(new byte[] { 0x0A });
        int length = ASN1Util.readLength(s, 100, false);