Add Currency.random() function

Author: nholland94

CodaClient.py

@@ -1,5 +1,6 @@
 #!/usr/bin/python3
 
+import random
 import requests
 import time
 import json
@@ -32,6 +33,18 @@ def __nanocodas_from_string(_cls, s):
       else:
         raise Exception('invalid coda currency format: %s' % s)
 
+  @classmethod
+  def random(_cls, lower_bound, upper_bound):
+    if not (isinstance(lower_bound, Currency) and isinstance(upper_bound, Currency)):
+      raise Exception('invalid call to Currency.random: lower and upper bound must be instances of Currency')
+    if not upper_bound.nanocodas() >= lower_bound.nanocodas():
+      raise Exception('invalid call to Currency.random: upper_bound is not greater than lower_bound')
+    if lower_bound == upper_bound:
+      return lower_bound
+    bound_range = upper_bound.nanocodas() - lower_bound.nanocodas()
+    delta = random.randint(0, bound_range)
+    return lower_bound + Currency(delta, format=CurrencyFormat.NANO)
+
   def __init__(self, value, format=CurrencyFormat.WHOLE):
     if format == CurrencyFormat.WHOLE:
       if isinstance(value, int):

tests/test_currency.py

@@ -38,3 +38,9 @@ def test_mul_int():
 
 def test_mul_currency():
   assert (Currency(5) * Currency(2, format=CurrencyFormat.NANO)).nanocodas() == 10 * precision
+
+def test_random():
+  assert (Currency.random(Currency(5), Currency(5)).nanocodas() == 5 * precision)
+  for _ in range(25):
+    rand = Currency.random(Currency(3, format=CurrencyFormat.NANO), Currency(5, format=CurrencyFormat.NANO))
+    assert (3 <= rand.nanocodas () and rand.nanocodas() <= 5)