bigarray: Test that asarray(BigArray(...)) does not hang

It was hanging with NumPy-1.9 before 425dc5d1 (bigarray: Raise
IndexError for out-of-bound element access), because of the following
correct NumPy commit:

    https://github.com/numpy/numpy/commit/d36f8227

and in particular

    https://github.com/numpy/numpy/commit/d36f8227#diff-6d326badc0872de91e025cbfb0be1aafR522

That PySequence_Fast(obj)    (with obj being BigArray)

creates iterator on top of obj and before our previous IndexError fix in
425dc5d1, this was looping forever.

Test explicitly with both NumPy 1.8 and NumPy 1.9, that this construct
does not hang.

/cc @Tyagov

bigarray/tests/test_basic.py

@@ -19,7 +19,8 @@
 from wendelin.bigarray import BigArray
 from wendelin.bigfile import BigFile
 from wendelin.lib.mem import memcpy
-from numpy import ndarray, dtype, int32, uint32, uint8, all, zeros, arange, multiply, array_equal
+from numpy import ndarray, dtype, int32, uint32, uint8, all, zeros, arange, \
+        multiply, array_equal, asarray
 
 from pytest import raises
 
@@ -422,3 +423,14 @@ def test_bigarray_list():
     l  = list(A)
     assert isinstance(l, list)
     assert l == [0]*10
+
+
+def test_bigarray_to_ndarray():
+    Z  = BigFile_Zero(PS)
+    Zh = Z.fileh_open()
+    A = BigArray((10,), uint8, Zh)
+
+    # without IndexError on out-of-bound scalar access, the following
+    # - would work with numpy-1.8
+    # - would loop forever eating memory with numpy-1.9
+    a = asarray(A)

tox.ini

 # wendelin.core | tox setup
 [tox]
-envlist = py27-{ZODB3,ZODB4}, py34-ZODB4
+envlist = py27-{ZODB3,ZODB4}-{numpy18,numpy19}, py34-ZODB4-{numpy18,numpy19}
 # (NOTE ZODB3 does not work on python3)
 
 [testenv]
@@ -14,6 +14,9 @@ deps    =
     # latest current ZODB _4_
     ZODB4:  ZODB3 >=3.11
 
+    numpy18: numpy >=1.8.2, <1.9.0
+    numpy19: numpy >=1.9.2, <1.10.0
+
 
 commands= {envpython} setup.py test
 # XXX setenv = TMPDIR = ... ?  (so that /tmp is not on tmpfs and we don't run out of memory on bench)