Merge pull request #10970 from eric-wieser/cut-down-ctypeslib

WIP: Remove fragile use of  __array_interface__ in ctypeslib.as_array

1 files changed, 67 insertions, 10 deletions

diff --git a/numpy/tests/test_ctypeslib.py b/numpy/tests/test_ctypeslib.py
index 0f0d6dbc4..75ce9c8ca 100644
--- a/numpy/tests/test_ctypeslib.py
+++ b/numpy/tests/test_ctypeslib.py
@@ -4,9 +4,9 @@ import sys
 import pytest
 
 import numpy as np
-from numpy.ctypeslib import ndpointer, load_library
+from numpy.ctypeslib import ndpointer, load_library, as_array
 from numpy.distutils.misc_util import get_shared_lib_extension
-from numpy.testing import assert_, assert_raises
+from numpy.testing import assert_, assert_array_equal, assert_raises, assert_equal
 
 try:
     cdll = None
@@ -21,11 +21,12 @@ try:
 except ImportError:
     _HAS_CTYPE = False
 
+
+@pytest.mark.skipif(not _HAS_CTYPE,
+                    reason="ctypes not available in this python")
+@pytest.mark.skipif(sys.platform == 'cygwin',
+                    reason="Known to fail on cygwin")
 class TestLoadLibrary(object):
-    @pytest.mark.skipif(not _HAS_CTYPE,
-                        reason="ctypes not available in this python")
-    @pytest.mark.skipif(sys.platform == 'cygwin',
-                        reason="Known to fail on cygwin")
     def test_basic(self):
         try:
             # Should succeed
@@ -35,10 +36,6 @@ class TestLoadLibrary(object):
                    " (import error was: %s)" % str(e))
             print(msg)
 
-    @pytest.mark.skipif(not _HAS_CTYPE,
-                        reason="ctypes not available in this python")
-    @pytest.mark.skipif(sys.platform == 'cygwin',
-                        reason="Known to fail on cygwin")
     def test_basic2(self):
         # Regression for #801: load_library with a full library name
         # (including extension) does not work.
@@ -54,6 +51,7 @@ class TestLoadLibrary(object):
                    " (import error was: %s)" % str(e))
             print(msg)
 
+
 class TestNdpointer(object):
     def test_dtype(self):
         dt = np.intc
@@ -113,3 +111,62 @@ class TestNdpointer(object):
         a1 = ndpointer(dtype=np.float64)
         a2 = ndpointer(dtype=np.float64)
         assert_(a1 == a2)
+
+
+@pytest.mark.skipif(not _HAS_CTYPE,
+                    reason="ctypes not available on this python installation")
+class TestAsArray(object):
+    def test_array(self):
+        from ctypes import c_int
+
+        pair_t = c_int * 2
+        a = as_array(pair_t(1, 2))
+        assert_equal(a.shape, (2,))
+        assert_array_equal(a, np.array([1, 2]))
+        a = as_array((pair_t * 3)(pair_t(1, 2), pair_t(3, 4), pair_t(5, 6)))
+        assert_equal(a.shape, (3, 2))
+        assert_array_equal(a, np.array([[1, 2], [3, 4], [5, 6]]))
+
+    def test_pointer(self):
+        from ctypes import c_int, cast, POINTER
+
+        p = cast((c_int * 10)(*range(10)), POINTER(c_int))
+
+        a = as_array(p, shape=(10,))
+        assert_equal(a.shape, (10,))
+        assert_array_equal(a, np.arange(10))
+
+        a = as_array(p, shape=(2, 5))
+        assert_equal(a.shape, (2, 5))
+        assert_array_equal(a, np.arange(10).reshape((2, 5)))
+
+        # shape argument is required
+        assert_raises(TypeError, as_array, p)
+
+    def test_struct_array_pointer(self):
+        from ctypes import c_int16, Structure, pointer
+
+        class Struct(Structure):
+            _fields_ = [('a', c_int16)]
+
+        Struct3 = 3 * Struct
+
+        c_array = (2 * Struct3)(
+            Struct3(Struct(a=1), Struct(a=2), Struct(a=3)),
+            Struct3(Struct(a=4), Struct(a=5), Struct(a=6))
+        )
+
+        expected = np.array([
+            [(1,), (2,), (3,)],
+            [(4,), (5,), (6,)],
+        ], dtype=[('a', np.int16)])
+
+        def check(x):
+            assert_equal(x.dtype, expected.dtype)
+            assert_equal(x, expected)
+
+        # all of these should be equivalent
+        check(as_array(c_array))
+        check(as_array(pointer(c_array), shape=()))
+        check(as_array(pointer(c_array[0]), shape=(2,)))
+        check(as_array(pointer(c_array[0][0]), shape=(2, 3)))