Tighten "numpy_attributes" test to assert that it's actually using a property...

Tighten "numpy_attributes" test to assert that it's actually using a property call and not an attribute access.
Also add a test for the newly added "ndarray.data" property.

tests/run/numpy_attributes.pyx

 # mode: run
 # tag: numpy
 
+cimport cython
+
 import numpy as np
 cimport numpy as cnp
 
 cnp.import_array()
 
+
+@cython.test_assert_path_exists(
+    "//ReturnStatNode",
+    "//ReturnStatNode//IndexNode",
+    "//ReturnStatNode//IndexNode//SimpleCallNode",
+)
+@cython.test_fail_if_path_exists(
+    "//ReturnStatNode//AttributeNode",
+)
 def access_shape():
     """
     >>> access_shape()
     10
     """
     cdef cnp.ndarray[double, ndim=2, mode='c'] array_in = \
-                    1e10 * np.ones((10, 10))
+        1e10 * np.ones((10, 10))
 
     return array_in.shape[0]
 
+
+@cython.test_assert_path_exists(
+    "//ReturnStatNode",
+    "//ReturnStatNode//SimpleCallNode",
+)
+@cython.test_fail_if_path_exists(
+    "//ReturnStatNode//AttributeNode",
+)
 def access_size():
     """
     >>> access_size()
     100
     """
     cdef cnp.ndarray[double, ndim=2, mode='c'] array_in = \
-                    1e10 * np.ones((10, 10))
+        1e10 * np.ones((10, 10))
 
     return array_in.size
 
+
+@cython.test_assert_path_exists(
+    "//ReturnStatNode",
+    "//ReturnStatNode//IndexNode",
+    "//ReturnStatNode//IndexNode//SimpleCallNode",
+)
+@cython.test_fail_if_path_exists(
+    "//ReturnStatNode//AttributeNode",
+)
 def access_strides():
     """
     >>> access_strides()
     (80, 8)
     """
     cdef cnp.ndarray[double, ndim=2, mode='c'] array_in = \
-                    1e10 * np.ones((10, 10), dtype=np.float64)
+        1e10 * np.ones((10, 10), dtype=np.float64)
 
     return (array_in.strides[0], array_in.strides[1])
+
+
+@cython.test_assert_path_exists(
+    "//ReturnStatNode",
+    "//ReturnStatNode//PrimaryCmpNode",
+    "//ReturnStatNode//PrimaryCmpNode//SimpleCallNode",
+)
+@cython.test_fail_if_path_exists(
+    "//ReturnStatNode//AttributeNode",
+)
+def access_data():
+    """
+    >>> access_data()
+    True
+    """
+    cdef cnp.ndarray[double, ndim=2, mode='c'] array_in = \
+        1e10 * np.ones((10, 10), dtype=np.float64)
+
+    return array_in.data is not NULL