From ff4488eed51dfd121541f1dcaafd41e1ce2b0bee Mon Sep 17 00:00:00 2001
From: Jude Nelson <judecn@gmail.com>
Date: Mon, 23 Apr 2018 16:16:38 -0400
Subject: [PATCH] add doctests to b40 module

---
 blockstack/lib/b40.py | 63 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/blockstack/lib/b40.py b/blockstack/lib/b40.py
index 902a42243..1b8e3d84b 100644
--- a/blockstack/lib/b40.py
+++ b/blockstack/lib/b40.py
@@ -34,25 +34,57 @@ B16_REGEX = '^[0-9a-f]*$'
 
 def int_to_charset(val, charset):
     """ Turn a non-negative integer into a string.
+
+    >>> int_to_charset(0, B40_CHARS)
+    '0'
+    >>> int_to_charset(658093, B40_CHARS)
+    'abcd'
+    >>> int_to_charset(40, B40_CHARS)
+    '10'
+    >>> int_to_charset(149190078205533, B40_CHARS)
+    'muneeb.id'
+    >>> int_to_charset(-1, B40_CHARS)
+    Traceback (most recent call last):
+        ...
+    ValueError: "val" must be a non-negative integer.
     """
-    if not val >= 0:
+    if val < 0:
         raise ValueError('"val" must be a non-negative integer.')
+
     if val == 0:
         return charset[0]
+
     output = ""
     while val > 0:
         val, digit = divmod(val, len(charset))
         output += charset[digit]
+
     # reverse the characters in the output and return
     return output[::-1]
 
 
 def charset_to_int(s, charset):
     """ Turn a string into a non-negative integer.
+
+    >>> charset_to_int('0', B40_CHARS)
+    0
+    >>> charset_to_int('10', B40_CHARS)
+    40
+    >>> charset_to_int('abcd', B40_CHARS)
+    658093
+    >>> charset_to_int('', B40_CHARS)
+    0
+    >>> charset_to_int('muneeb.id', B40_CHARS)
+    149190078205533
+    >>> charset_to_int('A', B40_CHARS)
+    Traceback (most recent call last):
+        ...
+    ValueError: substring not found
     """
     output = 0
     for char in s:
         output = output * len(charset) + charset.index(char)
+
     return output
 
 
@@ -68,6 +100,12 @@ def change_charset(s, original_charset, target_charset):
 
 
 def hexpad(x):
+    """
+    >>> hexpad('123')
+    '0123'
+    >>> hexpad('1234')
+    '1234'
+    """
     return ('0' * (len(x) % 2)) + x
 
 
@@ -78,11 +116,28 @@ def charset_to_hex(s, original_charset):
 def hex_to_charset(s, destination_charset):
     if not virtualchain.lib.hashing.is_hex(s):
         raise ValueError("Value must be in hex format")
+
     s = s.lower()
     return change_charset(s, B16_CHARS, destination_charset)
 
 
 def is_b40(s):
+    """
+    >>> is_b40('abcd')
+    True
+    >>> is_b40(u'abcd')
+    False
+    >>> is_b40(None)
+    False
+    >>> is_b40(123)
+    False
+    >>> is_b40('1234567890')
+    True
+    >>> is_b40('abcd.efgh+-_')
+    True
+    >>> is_b40('')
+    True
+    """
     return (isinstance(s, str) and (re.match(B40_REGEX, s) is not None))
 
 
@@ -100,3 +155,9 @@ def bin_to_b40(s):
 
 def b40_to_hex(s):
     return hexlify(b40_to_bin(s))
+
+
+if __name__ == '__main__':
+    import doctest
+    doctest.testmod()
+