add test helper module from cookiecutter

Author: phobson

probscale/tests/helpers.py

@@ -0,0 +1,12 @@
+from functools import wraps
+
+import numpy
+
+
+def seed(func):
+    """ Decorator to seed the RNG before any function. """
+    @wraps(func)
+    def wrapper(*args, **kwargs):
+        numpy.random.seed(0)
+        return func(*args, **kwargs)
+    return wrapper