fuzzy: Fix decimal.FloatOperation warning (Closes #261)

Under Python 2.7+, the previous versions was directly casting fuzzy
Decimal values into a float, which led to warnings in code trying to
avoid such conversions in its tested code.

Since we're just building random values, that behavior led to false
positives or required jumping through weird hoops whenever a
FuzzyDecimal was used.

We now go trough a ``str()`` call to avoid such warnings.

3 files changed, 13 insertions, 9 deletions

diff --git a/factory/compat.py b/factory/compat.py
index 785d174..737d91a 100644
--- a/factory/compat.py
+++ b/factory/compat.py
@@ -42,14 +42,6 @@ else:  # pragma: no cover
     from io import BytesIO
 
 
-if sys.version_info[:2] == (2, 6):  # pragma: no cover
-    def float_to_decimal(fl):
-        return decimal.Decimal(str(fl))
-else:  # pragma: no cover
-    def float_to_decimal(fl):
-        return decimal.Decimal(fl)
-
-
 try:  # pragma: no cover
     # Python >= 3.2
     UTC = datetime.timezone.utc
diff --git a/factory/fuzzy.py b/factory/fuzzy.py
index 923d8b7..a7e834c 100644
--- a/factory/fuzzy.py
+++ b/factory/fuzzy.py
@@ -164,7 +164,7 @@ class FuzzyDecimal(BaseFuzzyAttribute):
         super(FuzzyDecimal, self).__init__(**kwargs)
 
     def fuzz(self):
-        base = compat.float_to_decimal(_random.uniform(self.low, self.high))
+        base = decimal.Decimal(str(_random.uniform(self.low, self.high)))
         return base.quantize(decimal.Decimal(10) ** -self.precision)
 
 
diff --git a/tests/test_fuzzy.py b/tests/test_fuzzy.py
index 3f9c434..d83f3dd 100644
--- a/tests/test_fuzzy.py
+++ b/tests/test_fuzzy.py
@@ -189,6 +189,18 @@ class FuzzyDecimalTestCase(unittest.TestCase):
 
         self.assertEqual(decimal.Decimal('8.001').quantize(decimal.Decimal(10) ** -3), res)
 
+    def test_no_approximation(self):
+        """We should not go through floats in our fuzzy calls unless actually needed."""
+        fuzz = fuzzy.FuzzyDecimal(0, 10)
+
+        decimal_context = decimal.getcontext()
+        old_traps = decimal_context.traps[decimal.FloatOperation]
+        try:
+            decimal_context.traps[decimal.FloatOperation] = True
+            fuzz.evaluate(2, None, None)
+        finally:
+            decimal_context.traps[decimal.FloatOperation] = old_traps
+
 
 class FuzzyDateTestCase(unittest.TestCase):
     @classmethod