cpython/Lib/test/test_memoryview.py

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"""Unit tests for the memoryview
XXX We need more tests! Some tests are in test_bytes
"""
import unittest
import test.support
import sys
import gc
import weakref
class CommonMemoryTests:
#
# Tests common to direct memoryviews and sliced memoryviews
#
base_object = b"abcdef"
def check_getitem_with_type(self, tp):
b = tp(self.base_object)
oldrefcount = sys.getrefcount(b)
m = self._view(b)
self.assertEquals(m[0], b"a")
self.assert_(isinstance(m[0], bytes), type(m[0]))
self.assertEquals(m[5], b"f")
self.assertEquals(m[-1], b"f")
self.assertEquals(m[-6], 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_readonly(self):
self.check_getitem_with_type(bytes)
def test_getitem_writable(self):
self.check_getitem_with_type(bytearray)
def test_setitem_readonly(self):
b = self.base_object
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):
b = bytearray(self.base_object)
oldrefcount = sys.getrefcount(b)
m = self._view(b)
m[0] = b"0"
self._check_contents(b, b"0bcdef")
m[1:3] = b"12"
self._check_contents(b, b"012def")
m[1:1] = b""
self._check_contents(b, b"012def")
m[:] = b"abcdef"
self._check_contents(b, b"abcdef")
# Overlapping copies of a view into itself
m[0:3] = m[2:5]
self._check_contents(b, b"cdedef")
m[:] = b"abcdef"
m[2:5] = m[0:3]
self._check_contents(b, b"ababcf")
def setitem(key, value):
m[key] = 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_len(self):
self.assertEquals(len(self._view(self.base_object)), 6)
def test_tobytes(self):
m = self._view(self.base_object)
b = m.tobytes()
self.assertEquals(b, b"abcdef")
self.assert_(isinstance(b, bytes), type(b))
def test_tolist(self):
m = self._view(self.base_object)
l = m.tolist()
self.assertEquals(l, list(b"abcdef"))
def test_compare(self):
# memoryviews can compare for equality with other objects
# having the buffer interface.
m = self._view(self.base_object)
for tp in (bytes, bytearray):
self.assertTrue(m == tp(b"abcdef"))
self.assertFalse(m != tp(b"abcdef"))
self.assertFalse(m == tp(b"abcde"))
self.assertTrue(m != tp(b"abcde"))
self.assertFalse(m == tp(b"abcde1"))
self.assertTrue(m != tp(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 == "abc")
self.assertTrue(m != "abc")
self.assertFalse("abc" == m)
self.assertTrue("abc" != m)
# Unordered comparisons
for c in (m, b"abcdef"):
self.assertRaises(TypeError, lambda: m < c)
self.assertRaises(TypeError, lambda: c <= m)
self.assertRaises(TypeError, lambda: m >= c)
self.assertRaises(TypeError, lambda: c > m)
def check_attributes_with_type(self, tp):
b = tp(self.base_object)
m = self._view(b)
self.assertEquals(m.format, 'B')
self.assertEquals(m.itemsize, 1)
self.assertEquals(m.ndim, 1)
self.assertEquals(m.shape, (6,))
self.assertEquals(len(m), 6)
self.assertEquals(m.strides, (1,))
self.assertEquals(m.suboffsets, None)
return m
def test_attributes_readonly(self):
m = self.check_attributes_with_type(bytes)
self.assertEquals(m.readonly, True)
def test_attributes_writable(self):
m = self.check_attributes_with_type(bytearray)
self.assertEquals(m.readonly, False)
def test_getbuffer(self):
# Test PyObject_GetBuffer() on a memoryview object.
b = self.base_object
oldrefcount = sys.getrefcount(b)
m = self._view(b)
oldviewrefcount = sys.getrefcount(m)
s = str(m, "utf-8")
self._check_contents(b, s.encode("utf-8"))
self.assertEquals(sys.getrefcount(m), oldviewrefcount)
m = None
self.assertEquals(sys.getrefcount(b), oldrefcount)
def test_gc(self):
class MyBytes(bytes):
pass
class MyObject:
pass
# Create a reference cycle through a memoryview object
b = MyBytes(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())
class MemoryviewTest(unittest.TestCase, CommonMemoryTests):
def _view(self, obj):
return memoryview(obj)
def _check_contents(self, obj, contents):
self.assertEquals(obj, contents)
def test_constructor(self):
ob = b'test'
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 MemorySliceTest(unittest.TestCase, CommonMemoryTests):
base_object = b"XabcdefY"
def _view(self, obj):
m = memoryview(obj)
return m[1:7]
def _check_contents(self, obj, contents):
self.assertEquals(obj[1:7], contents)
def test_refs(self):
m = memoryview(b"ab")
oldrefcount = sys.getrefcount(m)
m[1:2]
self.assertEquals(sys.getrefcount(m), oldrefcount)
class MemorySliceSliceTest(unittest.TestCase, CommonMemoryTests):
base_object = b"XabcdefY"
def _view(self, obj):
m = memoryview(obj)
return m[:7][1:]
def _check_contents(self, obj, contents):
self.assertEquals(obj[1:7], contents)
def test_main():
test.support.run_unittest(
MemoryviewTest, MemorySliceTest, MemorySliceSliceTest)
if __name__ == "__main__":
test_main()