Fix binary operations in NumPy 1.8

Also allow reconfigure travis to check this.

Close #73

.travis.yml

@@ -30,10 +30,3 @@ matrix:
           env: NUMPY_VERSION=1.6
         - python: "3.3"
           env: NUMPY_VERSION=1.6
-    allow_failures:
-        - python: "2.7"
-          env: NUMPY_VERSION=1.8
-        - python: "3.2"
-          env: NUMPY_VERSION=1.8
-        - python: "3.3"
-          env: NUMPY_VERSION=1.8

CHANGES

@@ -12,6 +12,8 @@ Pint Changelog
 - Implemented default formatting for quantities.
 - Changed comparison between Quantities containing NumPy arrays.
   (Issue #75) - BACKWARDS INCOMPATIBLE CHANGE
+- Fixes for NumPy 1.8 due to changes in handling binary ops.
+  (Issue #73)
 
 
 0.3.3 (2013-11-29)
@@ -22,7 +24,9 @@ Pint Changelog
 - Fix comparison of quantities.
   (Issue #74)
 - Fix Inequality operator.
-  (Issue #70)
+  (Issue #70, thanks muggenhor)
+- Improved travis configuration.
+  (thanks muggenhor)
 
 
 0.3.2 (2013-10-22)

pint/quantity.py

@@ -301,7 +301,8 @@ class _Quantity(object):
     def __sub__(self, other):
         return self.add_sub(other, operator.isub)
 
-    __rsub__ = __sub__
+    def __rsub__(self, other):
+        return -self.add_sub(other, operator.isub)
 
     def __imul__(self, other):
         if _check(self, other):

pint/testsuite/__init__.py

@@ -11,9 +11,11 @@ try:
     import numpy as np
     HAS_NUMPY = True
     ndarray = np.ndarray
+    NUMPY_VER = np.__version__
 except ImportError:
     np = None
     HAS_NUMPY = False
+    NUMPY_VER = 0
     class ndarray(object):
         pass
 

pint/testsuite/test_issues.py

@@ -8,7 +8,7 @@ from pint import UnitRegistry
 from pint.unit import UnitsContainer
 from pint.util import ParserHelper
 
-from pint.testsuite import HAS_NUMPY, np, TestCase, ndarray
+from pint.testsuite import HAS_NUMPY, np, TestCase, ndarray, NUMPY_VER
 
 class TestIssues(unittest.TestCase):