ENH: enable debug session for appveyor

Author: yarikoptic

.travis.yml

@@ -2,16 +2,12 @@
 # CI on Windows via appveyor
 
 environment:
-
+  appveyor_build_worker_cloud: gce
   matrix:
-    - PYTHON: C:\Python27
-    - PYTHON: C:\Python27-x64
     - PYTHON: C:\Python34
     - PYTHON: C:\Python34-x64
     - PYTHON: C:\Python35
     - PYTHON: C:\Python35-x64
-    - PYTHON: C:\Python36
-    - PYTHON: C:\Python36-x64
 
 install:
   # Prepend newly installed Python to the PATH of this build (this cannot be
@@ -31,4 +27,14 @@ test_script:
   # Change into an innocuous directory and find tests from installation
   - mkdir for_testing
   - cd for_testing
-  - nosetests --with-doctest nibabel
+  # Print Python, numpy versions
+  - python -c "import sys, numpy; print('Python', sys.version); print('numpy', numpy.__version__)"
+  # Show all environment variables to ease possible future debugging
+  - set
+  - nosetests --with-doctest -s -v nibabel
+
+
+on_failure:
+  # enable the next to let the build VM block for up to 60min to log in via RDP and debug
+  # - ps: $blockRdp = $true; iex ((new-object net.webclient).DownloadString('https://rg.gosu.cc/appveyor/ci/master/scripts/enable-rdp.ps1'))
+

appveyor.yml

@@ -86,3 +86,10 @@ def test(*args, **kwargs):
 
 def get_info():
     return _get_pkg_info(os.path.dirname(__file__))
+
+def print_numpy_info():
+    import numpy as np
+    print("NUMPY:  ID(numpy): %d   ID(numpy.float64): %d" % (id(np), id(np.float64)))
+
+def setup_package():
+    print_numpy_info()

nibabel/__init__.py

@@ -7,6 +7,7 @@
 #
 ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ### ##
 from __future__ import division, print_function, absolute_import
+import sys
 
 from os.path import join as pjoin
 
@@ -156,7 +157,17 @@ def test_mincfile(self):
         for tp in self.test_files:
             mnc_obj = self.opener(tp['fname'], 'r')
             mnc = self.file_class(mnc_obj)
-            assert_equal(mnc.get_data_dtype().type, tp['dtype'])
+            try:
+                assert_equal(mnc.get_data_dtype().type, tp['dtype'])
+            except AssertionError:
+                from nibabel import print_numpy_info
+                print()
+                for l, t in (('mnc.get_data_dtype().type', mnc.get_data_dtype().type),
+                             ("tp['dtype']", tp['dtype'])):
+                    print("%30s  ID: %s, __module__: %s, id(sys[__module__]): %s"
+                          % (l, id(t), t.__module__, id(sys.modules[t.__module__])))
+                print_numpy_info()
+                raise
             assert_equal(mnc.get_data_shape(), tp['shape'])
             assert_equal(mnc.get_zooms(), tp['zooms'])
             assert_array_equal(mnc.get_affine(), tp['affine'])