Issue #2396: backport the memoryview object.

1 files changed, 328 insertions, 0 deletions

diff --git a/Lib/test/test_memoryview.py b/Lib/test/test_memoryview.py
new file mode 100644
index 0000000..c63ff5a
--- /dev/null
+++ b/Lib/test/test_memoryview.py
@@ -0,0 +1,328 @@
+"""Unit tests for the memoryview
+
+XXX We need more tests! Some tests are in test_bytes
+"""
+
+import unittest
+import sys
+import gc
+import weakref
+import array
+from test import test_support
+
+
+class AbstractMemoryTests:
+    source_bytes = b"abcdef"
+
+    @property
+    def _source(self):
+        return self.source_bytes
+
+    @property
+    def _types(self):
+        return filter(None, [self.ro_type, self.rw_type])
+
+    def check_getitem_with_type(self, tp):
+        item = self.getitem_type
+        b = tp(self._source)
+        oldrefcount = sys.getrefcount(b)
+        m = self._view(b)
+        self.assertEquals(m[0], item(b"a"))
+        self.assert_(isinstance(m[0], bytes), type(m[0]))
+        self.assertEquals(m[5], item(b"f"))
+        self.assertEquals(m[-1], item(b"f"))
+        self.assertEquals(m[-6], item(b"a"))
+        # Bounds checking
+        self.assertRaises(IndexError, lambda: m[6])
+        self.assertRaises(IndexError, lambda: m[-7])
+        self.assertRaises(IndexError, lambda: m[sys.maxsize])
+        self.assertRaises(IndexError, lambda: m[-sys.maxsize])
+        # Type checking
+        self.assertRaises(TypeError, lambda: m[None])
+        self.assertRaises(TypeError, lambda: m[0.0])
+        self.assertRaises(TypeError, lambda: m["a"])
+        m = None
+        self.assertEquals(sys.getrefcount(b), oldrefcount)
+
+    def test_getitem(self):
+        for tp in self._types:
+            self.check_getitem_with_type(tp)
+
+    def test_setitem_readonly(self):
+        if not self.ro_type:
+            return
+        b = self.ro_type(self._source)
+        oldrefcount = sys.getrefcount(b)
+        m = self._view(b)
+        def setitem(value):
+            m[0] = value
+        self.assertRaises(TypeError, setitem, b"a")
+        self.assertRaises(TypeError, setitem, 65)
+        self.assertRaises(TypeError, setitem, memoryview(b"a"))
+        m = None
+        self.assertEquals(sys.getrefcount(b), oldrefcount)
+
+    def test_setitem_writable(self):
+        if not self.rw_type:
+            return
+        tp = self.rw_type
+        b = self.rw_type(self._source)
+        oldrefcount = sys.getrefcount(b)
+        m = self._view(b)
+        m[0] = tp(b"0")
+        self._check_contents(tp, b, b"0bcdef")
+        m[1:3] = tp(b"12")
+        self._check_contents(tp, b, b"012def")
+        m[1:1] = tp(b"")
+        self._check_contents(tp, b, b"012def")
+        m[:] = tp(b"abcdef")
+        self._check_contents(tp, b, b"abcdef")
+
+        # Overlapping copies of a view into itself
+        m[0:3] = m[2:5]
+        self._check_contents(tp, b, b"cdedef")
+        m[:] = tp(b"abcdef")
+        m[2:5] = m[0:3]
+        self._check_contents(tp, b, b"ababcf")
+
+        def setitem(key, value):
+            m[key] = tp(value)
+        # Bounds checking
+        self.assertRaises(IndexError, setitem, 6, b"a")
+        self.assertRaises(IndexError, setitem, -7, b"a")
+        self.assertRaises(IndexError, setitem, sys.maxsize, b"a")
+        self.assertRaises(IndexError, setitem, -sys.maxsize, b"a")
+        # Wrong index/slice types
+        self.assertRaises(TypeError, setitem, 0.0, b"a")
+        self.assertRaises(TypeError, setitem, (0,), b"a")
+        self.assertRaises(TypeError, setitem, "a", b"a")
+        # Trying to resize the memory object
+        self.assertRaises(ValueError, setitem, 0, b"")
+        self.assertRaises(ValueError, setitem, 0, b"ab")
+        self.assertRaises(ValueError, setitem, slice(1,1), b"a")
+        self.assertRaises(ValueError, setitem, slice(0,2), b"a")
+
+        m = None
+        self.assertEquals(sys.getrefcount(b), oldrefcount)
+
+    def test_tobytes(self):
+        for tp in self._types:
+            m = self._view(tp(self._source))
+            b = m.tobytes()
+            # This calls self.getitem_type() on each separate byte of b"abcdef"
+            expected = b"".join(
+                self.getitem_type(c) for c in b"abcdef")
+            self.assertEquals(b, expected)
+            self.assert_(isinstance(b, bytes), type(b))
+
+    def test_tolist(self):
+        for tp in self._types:
+            m = self._view(tp(self._source))
+            l = m.tolist()
+            self.assertEquals(l, map(ord, b"abcdef"))
+
+    def test_compare(self):
+        # memoryviews can compare for equality with other objects
+        # having the buffer interface.
+        for tp in self._types:
+            m = self._view(tp(self._source))
+            for tp_comp in self._types:
+                self.assertTrue(m == tp_comp(b"abcdef"))
+                self.assertFalse(m != tp_comp(b"abcdef"))
+                self.assertFalse(m == tp_comp(b"abcde"))
+                self.assertTrue(m != tp_comp(b"abcde"))
+                self.assertFalse(m == tp_comp(b"abcde1"))
+                self.assertTrue(m != tp_comp(b"abcde1"))
+            self.assertTrue(m == m)
+            self.assertTrue(m == m[:])
+            self.assertTrue(m[0:6] == m[:])
+            self.assertFalse(m[0:5] == m)
+
+            # Comparison with objects which don't support the buffer API
+            self.assertFalse(m == u"abcdef")
+            self.assertTrue(m != u"abcdef")
+            self.assertFalse(u"abcdef" == m)
+            self.assertTrue(u"abcdef" != m)
+
+            # Unordered comparisons are unimplemented, and therefore give
+            # arbitrary results (they raise a TypeError in py3k)
+
+    def check_attributes_with_type(self, tp):
+        m = self._view(tp(self._source))
+        self.assertEquals(m.format, self.format)
+        self.assertEquals(m.itemsize, self.itemsize)
+        self.assertEquals(m.ndim, 1)
+        self.assertEquals(m.shape, (6,))
+        self.assertEquals(len(m), 6)
+        self.assertEquals(m.strides, (self.itemsize,))
+        self.assertEquals(m.suboffsets, None)
+        return m
+
+    def test_attributes_readonly(self):
+        if not self.ro_type:
+            return
+        m = self.check_attributes_with_type(self.ro_type)
+        self.assertEquals(m.readonly, True)
+
+    def test_attributes_writable(self):
+        if not self.rw_type:
+            return
+        m = self.check_attributes_with_type(self.rw_type)
+        self.assertEquals(m.readonly, False)
+
+    # Disabled: unicode uses the old buffer API in 2.x
+
+    #def test_getbuffer(self):
+        ## Test PyObject_GetBuffer() on a memoryview object.
+        #for tp in self._types:
+            #b = tp(self._source)
+            #oldrefcount = sys.getrefcount(b)
+            #m = self._view(b)
+            #oldviewrefcount = sys.getrefcount(m)
+            #s = unicode(m, "utf-8")
+            #self._check_contents(tp, b, s.encode("utf-8"))
+            #self.assertEquals(sys.getrefcount(m), oldviewrefcount)
+            #m = None
+            #self.assertEquals(sys.getrefcount(b), oldrefcount)
+
+    def test_gc(self):
+        for tp in self._types:
+            if not isinstance(tp, type):
+                # If tp is a factory rather than a plain type, skip
+                continue
+
+            class MySource(tp):
+                pass
+            class MyObject:
+                pass
+
+            # Create a reference cycle through a memoryview object
+            b = MySource(tp(b'abc'))
+            m = self._view(b)
+            o = MyObject()
+            b.m = m
+            b.o = o
+            wr = weakref.ref(o)
+            b = m = o = None
+            # The cycle must be broken
+            gc.collect()
+            self.assert_(wr() is None, wr())
+
+
+# Variations on source objects for the buffer: bytes-like objects, then arrays
+# with itemsize > 1.
+# NOTE: support for multi-dimensional objects is unimplemented.
+
+class BaseBytesMemoryTests(AbstractMemoryTests):
+    ro_type = bytes
+    rw_type = bytearray
+    getitem_type = bytes
+    itemsize = 1
+    format = 'B'
+
+# Disabled: array.array() does not support the new buffer API in 2.x
+
+#class BaseArrayMemoryTests(AbstractMemoryTests):
+    #ro_type = None
+    #rw_type = lambda self, b: array.array('i', map(ord, b))
+    #getitem_type = lambda self, b: array.array('i', map(ord, b)).tostring()
+    #itemsize = array.array('i').itemsize
+    #format = 'i'
+
+    #def test_getbuffer(self):
+        ## XXX Test should be adapted for non-byte buffers
+        #pass
+
+    #def test_tolist(self):
+        ## XXX NotImplementedError: tolist() only supports byte views
+        #pass
+
+
+# Variations on indirection levels: memoryview, slice of memoryview,
+# slice of slice of memoryview.
+# This is important to test allocation subtleties.
+
+class BaseMemoryviewTests:
+    def _view(self, obj):
+        return memoryview(obj)
+
+    def _check_contents(self, tp, obj, contents):
+        self.assertEquals(obj, tp(contents))
+
+class BaseMemorySliceTests:
+    source_bytes = b"XabcdefY"
+
+    def _view(self, obj):
+        m = memoryview(obj)
+        return m[1:7]
+
+    def _check_contents(self, tp, obj, contents):
+        self.assertEquals(obj[1:7], tp(contents))
+
+    def test_refs(self):
+        for tp in self._types:
+            m = memoryview(tp(self._source))
+            oldrefcount = sys.getrefcount(m)
+            m[1:2]
+            self.assertEquals(sys.getrefcount(m), oldrefcount)
+
+class BaseMemorySliceSliceTests:
+    source_bytes = b"XabcdefY"
+
+    def _view(self, obj):
+        m = memoryview(obj)
+        return m[:7][1:]
+
+    def _check_contents(self, tp, obj, contents):
+        self.assertEquals(obj[1:7], tp(contents))
+
+
+# Concrete test classes
+
+class BytesMemoryviewTest(unittest.TestCase,
+    BaseMemoryviewTests, BaseBytesMemoryTests):
+
+    def test_constructor(self):
+        for tp in self._types:
+            ob = tp(self._source)
+            self.assert_(memoryview(ob))
+            self.assert_(memoryview(object=ob))
+            self.assertRaises(TypeError, memoryview)
+            self.assertRaises(TypeError, memoryview, ob, ob)
+            self.assertRaises(TypeError, memoryview, argument=ob)
+            self.assertRaises(TypeError, memoryview, ob, argument=True)
+
+#class ArrayMemoryviewTest(unittest.TestCase,
+    #BaseMemoryviewTests, BaseArrayMemoryTests):
+
+    #def test_array_assign(self):
+        ## Issue #4569: segfault when mutating a memoryview with itemsize != 1
+        #a = array.array('i', range(10))
+        #m = memoryview(a)
+        #new_a = array.array('i', range(9, -1, -1))
+        #m[:] = new_a
+        #self.assertEquals(a, new_a)
+
+
+class BytesMemorySliceTest(unittest.TestCase,
+    BaseMemorySliceTests, BaseBytesMemoryTests):
+    pass
+
+#class ArrayMemorySliceTest(unittest.TestCase,
+    #BaseMemorySliceTests, BaseArrayMemoryTests):
+    #pass
+
+class BytesMemorySliceSliceTest(unittest.TestCase,
+    BaseMemorySliceSliceTests, BaseBytesMemoryTests):
+    pass
+
+#class ArrayMemorySliceSliceTest(unittest.TestCase,
+    #BaseMemorySliceSliceTests, BaseArrayMemoryTests):
+    #pass
+
+
+def test_main():
+    test_support.run_unittest(__name__)
+
+if __name__ == "__main__":
+    test_main()