BF - set explicit dtype when creating test images

In commit 6501b44 I was creating images by passing in arrays of the
default platform integer type.  This is int64 for 64 bit platforms, and
analyze images don't support int64.  I set the dtype specifically to
int16 which (currently) all images can support.

Author: matthew-brett

nibabel/tests/test_spatialimages.py

@@ -211,25 +211,33 @@ def test_data_default(self):
     def test_data_shape(self):
         # Check shape correctly read
         img_klass = self.image_class
-        img = img_klass(np.arange(4), np.eye(4))
+        # Assumes all possible images support int16
+        # See https://github.com/nipy/nibabel/issues/58
+        arr = np.arange(4, dtype=np.int16)
+        img = img_klass(arr, np.eye(4))
         assert_equal(img.shape, (4,))
         img = img_klass(np.zeros((2,3,4)), np.eye(4))
         assert_equal(img.shape, (2,3,4))
 
     def test_str(self):
         # Check something comes back from string representation
         img_klass = self.image_class
-        img = img_klass(np.arange(5), np.eye(4))
+        # Assumes all possible images support int16
+        # See https://github.com/nipy/nibabel/issues/58
+        arr = np.arange(5, dtype=np.int16)
+        img = img_klass(arr, np.eye(4))
         assert_true(len(str(img)) > 0)
         assert_equal(img.shape, (5,))
-        img = img_klass(np.zeros((2,3,4)), np.eye(4))
+        img = img_klass(np.zeros((2,3,4), dtype=np.int16), np.eye(4))
         assert_true(len(str(img)) > 0)
 
     def test_get_shape(self):
         # Check there is a get_shape method
         # (it is deprecated)
         img_klass = self.image_class
-        img = img_klass(np.arange(1), np.eye(4))
+        # Assumes all possible images support int16
+        # See https://github.com/nipy/nibabel/issues/58
+        img = img_klass(np.arange(1, dtype=np.int16), np.eye(4))
         assert_equal(img.get_shape(), (1,))
-        img = img_klass(np.zeros((2,3,4)), np.eye(4))
+        img = img_klass(np.zeros((2,3,4), np.int16), np.eye(4))
         assert_equal(img.get_shape(), (2,3,4))

nibabel/tests/test_spm99analyze.py

@@ -109,7 +109,7 @@ class TestSpm99AnalyzeImage(test_analyze.TestAnalyzeImage):
     def test_mat_read(self):
         # Test mat file reading and writing for the SPM analyze types
         img_klass = self.image_class
-        arr = np.arange(24).reshape((2,3,4))
+        arr = np.arange(24, dtype=np.int32).reshape((2,3,4))
         aff = np.diag([2,3,4,1]) # no LR flip in affine
         img = img_klass(arr, aff)
         fm = img.file_map