Convert a 15 character Salesforce Identier into an 18 character Identifier

id18.py

# suffix characters (base 32, sort of)
SUFFIX_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ012345"


def id18(s: str, *, check_suffix: bool = False) -> str:
    """
    Converts a 15 character Salesforce ID (s) to its 18 character version.

    If the ID provided has length 18 and check_suffix is True, we will assert
    that the suffix is correct!

    >>> assert id18("a0BA0000000L2ZC") == "a0BA0000000L2ZCMA0"
    >>> assert id18("AaaAABbbBBCccCC") == "AaaAABbbBBCccCCZZZ"
    >>> assert id18("ABCDEFGHIJKLMNO") == "ABCDEFGHIJKLMNO555"
    >>> assert id18("AAAAABBBBBCCCCC") == "AAAAABBBBBCCCCC555"
    >>> assert id18("ABCDEABCDEABCDE") == "ABCDEABCDEABCDE555"
    >>> assert id18("AAaAAbbBBBCcCCC") == "AAaAAbbBBBCcCCC123"
    """
    if not isinstance(s, str):
        raise TypeError("id must be type str")
    if "" in (s, s.strip()):
        raise ValueError("id must not be empty")
    if len(s) not in (15, 18):
        raise ValueError("id must have length 15, 18")

    def suffix(p: str) -> str:
        """
        Calculates the suffix for given a 15 character Salesforce ID
        """
        return "".join([
            SUFFIX_CHARS[sum(
                1 << i
                for i, c in enumerate(p[n:n+5])
                if c.isupper()
            )] for n in (0, 5, 10)
        ])

    if len(s) == 18:
        if check_suffix:
            exp, act = s[15:], suffix(s[:15])
            assert exp == act, f'id18: suffix mismatch for "{s}": "{exp}" != "{act}"'
        return s
  
    # length is 15; generate and return the id with the suffix
    return f"{s}{suffix(s)}"


if __name__ == "__main__":
    import doctest
    doctest.testmod()

id18_overengineered.py

from typing import List


def id18(s: str, *, check_suffix: bool = False) -> str:
    """
    Converts a 15 character Salesforce ID (s) to its 18 character version.

    If the ID provided has length 18 and check_suffix is True, we will assert
    that the suffix is correct!

    >>> assert id18("a0BA0000000L2ZC") == "a0BA0000000L2ZCMA0"
    >>> assert id18("AaaAABbbBBCccCC") == "AaaAABbbBBCccCCZZZ"
    >>> assert id18("ABCDEFGHIJKLMNO") == "ABCDEFGHIJKLMNO555"
    >>> assert id18("AAAAABBBBBCCCCC") == "AAAAABBBBBCCCCC555"
    >>> assert id18("ABCDEABCDEABCDE") == "ABCDEABCDEABCDE555"
    >>> assert id18("AAaAAbbBBBCcCCC") == "AAaAAbbBBBCcCCC123"
    >>> id18("")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in id18
    AssertionError: id18: id cannot be an empty string
    >>> id18("AbCdEfGhIjKlMn")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in id18
    AssertionError: id18: id must have length 15 or 18
    >>> id18("AbCdEfGhIjKlMnOpQrS")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in id18
    AssertionError: id18: id must have length 15 or 18
    >>> id18("AAaAAbbBBBCcCCC   ")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in id18
    AssertionError: id18: id cannot have trailing spaces
    >>> id18("   AAaAAbbBBBCcCCC")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in id18
    AssertionError: id18: id cannot have trailing spaces
    >>> id18(" AAaAAbbBBBCcCCC  ")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in id18
    AssertionError: id18: id cannot have trailing spaces
    """
    assert isinstance(s, str), "id18: id must be type str"
    assert len(s), "id18: id cannot be an empty string"
    assert s.strip() == s, "id18: id cannot have trailing spaces"
    assert len(s) in (15, 18), "id18: id must have length 15 or 18"
    if len(s) == 18:
        if check_suffix:
            exp, act = s[15:], suffix(s[:15])
            assert exp == act, f'id18: suffix mismatch for "{s}": "{exp}" != "{act}"'
        return s
    # length is 15; generate and return the ID with the suffix
    return f"{s}{suffix(s)}"


def quintets(s: str) -> List[str]:
    """
    >>> assert quintets("AAAAA") == ["AAAAA"]
    >>> assert quintets("AAAAABBBBB") == ["AAAAA", "BBBBB"]
    >>> assert quintets("AAAAABBBBBCCCCC") == ["AAAAA", "BBBBB", "CCCCC"]
    >>> quintets("")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in quintets
    AssertionError: quintets: argument cannot be an empty string
    >>> quintets("     ")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in quintets
    AssertionError: quintets: argument cannot have trailing spaces
    >>> quintets(" ABCD")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in quintets
    AssertionError: quintets: argument cannot have trailing spaces
    >>> quintets("ABCD ")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in quintets
    AssertionError: quintets: argument cannot have trailing spaces
    >>> quintets("   ABCD   ")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in quintets
    AssertionError: quintets: argument cannot have trailing spaces
    >>> quintets("ACBD")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in quintets
    AssertionError: quintets: argument length must be divisible by 5
    >>> quintets("ACBDEABCD")
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in quintets
    AssertionError: quintets: argument length must be divisible by 5
    """
    assert isinstance(s, str), "quintets: argument must be type str"
    assert len(s), "quintets: argument cannot be an empty string"
    assert s.strip() == s, "quintets: argument cannot have trailing spaces"
    assert len(s) and len(s) % 5 == 0, "quintets: argument length must be divisible by 5"
    # generate the list of quintets
    return list(s[n:n+5] for n in range(0, len(s), 5))


def suffix_char(i: int) -> str:
    """
    >>> assert suffix_char(0) == "A"
    >>> assert suffix_char(31) == "5"
    >>> assert "".join(suffix_char(n) for n in range(0, 32)) == "ABCDEFGHIJKLMNOPQRSTUVWXYZ012345"
    >>> suffix_char(-1)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in suffix_char
    AssertionError: suffix_char: invalid index -1
    >>> suffix_char(32)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in suffix_char
    AssertionError: suffix_char: invalid index 32
    >>> suffix_char(None)
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "<stdin>", line 1, in suffix_char
    AssertionError: suffix_char: index must be type int
    """
    assert isinstance(i, int), "suffix_char: index must be type int"
    assert 0 <= i <= 31, f"suffix_char: invalid index {i}"
    return "ABCDEFGHIJKLMNOPQRSTUVWXYZ012345"[i]


def suffix_index(s: str) -> int:
    assert isinstance(s, str), "suffix_index: argument must be type str"
    assert len(s), "suffix_index: argument cannot be an empty str"
    assert s.strip() == s, "suffix_index: argument cannot have trailing spaces"
    assert len(s) == 5, "suffix_index: argument must have length 5"
    idx = 0
    for i, c in enumerate(s):
        if c.isupper():
            idx += 1 << i
    return idx


def suffix(s: str) -> str:
    """
    >>> assert suffix("a0BA0000000L2ZC") == "MA0"
    >>> assert suffix("AaaAABbbBBCccCC") == "ZZZ"
    >>> assert suffix("ABCDEFGHIJKLMNO") == "555"
    >>> assert suffix("AAAAABBBBBCCCCC") == "555"
    >>> assert suffix("ABCDEABCDEABCDE") == "555"
    >>> assert suffix("AAaAAbbBBBCcCCC") == "123"
    """
    assert isinstance(s, str), "suffix: argument must be type str"
    assert s.strip() == s, "suffix: argument cannot have trailing spaces"
    assert len(s) == 15, "suffix: argument must have length 15"
    return "".join(suffix_char(suffix_index(q)) for q in quintets(s))


if __name__ == "__main__":
    import doctest
    doctest.testmod()