Added FuzzyText attribute.

Useful for unique model attributes where the specific value can be fuzzy.

3 files changed, 102 insertions, 1 deletions

diff --git a/docs/fuzzy.rst b/docs/fuzzy.rst
index d88cb5a..582a654 100644
--- a/docs/fuzzy.rst
+++ b/docs/fuzzy.rst
@@ -24,6 +24,35 @@ FuzzyAttribute
         The callable that generates random values
 
 
+FuzzyText
+---------
+
+
+.. class:: FuzzyText(length=12, chars=string.ascii_letters, prefix='')
+
+    The :class:`FuzzyText` fuzzer yields random strings beginning with
+    the given :attr:`prefix`, followed by :attr:`length` charactes chosen
+    from the :attr:`chars` character set,
+    and ending with the given :attr:`suffix`.
+
+    .. attribute:: length
+
+        int, the length of the random part
+
+    .. attribute:: prefix
+
+        text, an optional prefix to prepend to the random part
+
+    .. attribute:: suffix
+
+        text, an optional suffix to append to the random part
+
+    .. attribute:: chars
+
+        char iterable, the chars to choose from; defaults to the list of ascii
+            letters and numbers.
+
+
 FuzzyChoice
 -----------
 
diff --git a/factory/fuzzy.py b/factory/fuzzy.py
index d3b130b..f3e6a31 100644
--- a/factory/fuzzy.py
+++ b/factory/fuzzy.py
@@ -23,8 +23,11 @@
 
 """Additional declarations for "fuzzy" attribute definitions."""
 
+from __future__ import unicode_literals
+
 
 import random
+import string
 import datetime
 
 from . import compat
@@ -60,6 +63,36 @@ class FuzzyAttribute(BaseFuzzyAttribute):
         return self.fuzzer()
 
 
+class FuzzyText(BaseFuzzyAttribute):
+    """Random string with a given prefix.
+
+    Generates a random string of the given length from chosen chars.
+    If a prefix or a suffix are supplied, they will be prepended / appended
+    to the generated string.
+
+    Args:
+        prefix (text): An optional prefix to prepend to the random string
+        length (int): the length of the random part
+        suffix (text): An optional suffix to append to the random string
+        chars (str list): the chars to choose from
+
+    Useful for generating unique attributes where the exact value is
+    not important.
+    """
+
+    def __init__(self, prefix='', length=12, suffix='',
+        chars=string.ascii_letters, **kwargs):
+        super(FuzzyText, self).__init__(**kwargs)
+        self.prefix = prefix
+        self.suffix = suffix
+        self.length = length
+        self.chars = tuple(chars)  # Unroll iterators
+
+    def fuzz(self):
+        chars = [random.choice(self.chars) for _i in range(self.length)]
+        return self.prefix + ''.join(chars) + self.suffix
+
+
 class FuzzyChoice(BaseFuzzyAttribute):
     """Handles fuzzy choice of an attribute."""
 
diff --git a/tests/test_fuzzy.py b/tests/test_fuzzy.py
index 97abece..a521ee2 100644
--- a/tests/test_fuzzy.py
+++ b/tests/test_fuzzy.py
@@ -63,7 +63,7 @@ class FuzzyChoiceTestCase(unittest.TestCase):
         def options():
             for i in range(3):
                 yield i
-        
+
         d = fuzzy.FuzzyChoice(options())
 
         res = d.evaluate(2, None, False)
@@ -401,3 +401,42 @@ class FuzzyDateTimeTestCase(unittest.TestCase):
             res = fuzz.evaluate(2, None, False)
 
         self.assertEqual(datetime.datetime(2013, 1, 2, tzinfo=compat.UTC), res)
+
+
+class FuzzyTextTestCase(unittest.TestCase):
+
+    def test_unbiased(self):
+        chars = ['a', 'b', 'c']
+        fuzz = fuzzy.FuzzyText(prefix='pre', suffix='post', chars=chars, length=12)
+        res = fuzz.evaluate(2, None, False)
+
+        self.assertEqual('pre', res[:3])
+        self.assertEqual('post', res[-4:])
+        self.assertEqual(3 + 12 + 4, len(res))
+
+        for char in res[3:-4]:
+            self.assertIn(char, chars)
+
+    def test_mock(self):
+        fake_choice = lambda chars: chars[0]
+
+        chars = ['a', 'b', 'c']
+        fuzz = fuzzy.FuzzyText(prefix='pre', suffix='post', chars=chars, length=4)
+        with mock.patch('random.choice', fake_choice):
+            res = fuzz.evaluate(2, None, False)
+
+        self.assertEqual('preaaaapost', res)
+
+    def test_generator(self):
+        def options():
+            yield 'a'
+            yield 'b'
+            yield 'c'
+
+        fuzz = fuzzy.FuzzyText(chars=options(), length=12)
+        res = fuzz.evaluate(2, None, False)
+
+        self.assertEqual(12, len(res))
+
+        for char in res:
+            self.assertIn(char, ['a', 'b', 'c'])