Fix test output of Pythran test and give a better name to a test function.

tests/run/numpy_pythran.pyx

@@ -5,9 +5,9 @@
 import numpy as np
 cimport numpy as cnp
 
-def test():
+def diffuse():
     """
-    >>> u = test()
+    >>> u = diffuse()
     >>> count_non_zero = np.sum(u > 0)
     >>> 15000 < count_non_zero < (2**7) * (2**7) or count_non_zero
     True
@@ -15,11 +15,11 @@ def test():
     lx, ly = (2**7, 2**7)
     u = np.zeros([lx, ly], dtype=np.double)
     u[lx // 2, ly // 2] = 1000.0
-    diffuse_numpy(u, 500)
+    _diffuse_numpy(u, 500)
     return u
 
 
-def diffuse_numpy(cnp.ndarray[double, ndim=2] u, int N):
+def _diffuse_numpy(cnp.ndarray[double, ndim=2] u, int N):
     """
     Apply Numpy matrix for the Forward-Euler Approximation
     """
@@ -41,6 +41,7 @@ def calculate_tax(cnp.ndarray[double, ndim=1] d):
     >>> d = np.random.lognormal(mu, sigma, 10000)
     >>> avg = calculate_tax(d)
     >>> 0.243 < avg < 0.244 or avg  # 0.24342652180085891
+    True
     """
     tax_seg1 = d[(d > 256303)] * 0.45 - 16164.53
     tax_seg2 = d[(d > 54057) & (d <= 256303)] * 0.42 - 8475.44