add: dc=test
test: 3.1.1  First continuation byte 0x80: "�"
test: 3.1.2  Last  continuation byte 0xbf: "�"
test: 3.1.3  2 continuation bytes: "��"
test: 3.1.4  3 continuation bytes: "���"
test: 3.1.5  4 continuation bytes: "����"
test: 3.1.6  5 continuation bytes: "�����"
test: 3.1.7  6 continuation bytes: "������"
test: 3.1.8  7 continuation bytes: "�������"
test:    "����������������
test:     ����������������
test:     ����������������
test:     ����������������"
test:    "� � � � � � � � � � � � � � � �
test:     � � � � � � � � � � � � � � � � "
test:    "� � � � � � � � � � � � � � � � "
test:    "� � � � � � � � "
test:    "� � � � "
test:    "� � "
test: 3.3.1  2-byte sequence with last byte missing (U+0000):     "�"
test: 3.3.2  3-byte sequence with last byte missing (U+0000):     "��"
test: 3.3.3  4-byte sequence with last byte missing (U+0000):     "���"
test: 3.3.4  5-byte sequence with last byte missing (U+0000):     "����"
test: 3.3.5  6-byte sequence with last byte missing (U+0000):     "�����"
test: 3.3.6  2-byte sequence with last byte missing (U-000007FF): "�"
test: 3.3.7  3-byte sequence with last byte missing (U-0000FFFF): "�"
test: 3.3.8  4-byte sequence with last byte missing (U-001FFFFF): "���"
test: 3.3.9  5-byte sequence with last byte missing (U-03FFFFFF): "����"
test: 3.3.10 6-byte sequence with last byte missing (U-7FFFFFFF): "�����"
test:    "�����������������������������"
test: 3.5.1  fe = "�"
test: 3.5.2  ff = "�"
test: 3.5.3  fe fe ff ff = "����"
test: 4  Overlong sequences
test: 4.1.1 U+002F = c0 af             = "��"
test: 4.1.2 U+002F = e0 80 af          = "���"
test: 4.1.3 U+002F = f0 80 80 af       = "����"
test: 4.1.4 U+002F = f8 80 80 80 af    = "�����"
test: 4.1.5 U+002F = fc 80 80 80 80 af = "������"
test: 4.2.1  U-0000007F = c1 bf             = "��"
test: 4.2.2  U-000007FF = e0 9f bf          = "���"
test: 4.2.3  U-0000FFFF = f0 8f bf bf       = "����"
test: 4.2.4  U-001FFFFF = f8 87 bf bf bf    = "�����"
test: 4.2.5  U-03FFFFFF = fc 83 bf bf bf bf = "������"
test: 4.3.1  U+0000 = c0 80             = "��"
test: 4.3.2  U+0000 = e0 80 80          = "���"
test: 4.3.3  U+0000 = f0 80 80 80       = "����"
test: 4.3.4  U+0000 = f8 80 80 80 80    = "�����"
test: 4.3.5  U+0000 = fc 80 80 80 80 80 = "������"
test: 5  Illegal code positions
test: 5.1.1  U+D800 = ed a0 80 = "���"
test: 5.1.2  U+DB7F = ed ad bf = "���"
test: 5.1.3  U+DB80 = ed ae 80 = "���"
test: 5.1.4  U+DBFF = ed af bf = "���"
test: 5.1.5  U+DC00 = ed b0 80 = "���"
test: 5.1.6  U+DF80 = ed be 80 = "���"
test: 5.1.7  U+DFFF = ed bf bf = "���"
test: 5.2.1  U+D800 U+DC00 = ed a0 80 ed b0 80 = "������"
test: 5.2.2  U+D800 U+DFFF = ed a0 80 ed bf bf = "������"
test: 5.2.3  U+DB7F U+DC00 = ed ad bf ed b0 80 = "������"
test: 5.2.4  U+DB7F U+DFFF = ed ad bf ed bf bf = "������"
test: 5.2.5  U+DB80 U+DC00 = ed ae 80 ed b0 80 = "������"
test: 5.2.6  U+DB80 U+DFFF = ed ae 80 ed bf bf = "������"
test: 5.2.7  U+DBFF U+DC00 = ed af bf ed b0 80 = "������"
test: 5.2.8  U+DBFF U+DFFF = ed af bf ed bf bf = "������"
test: 5.3.1  U+FFFE = ef bf be = "￾"
test: 5.3.2  U+FFFF = ef bf bf = "￿"