def test_yieldable_for_new_initialized_buffer_work_space(self):
"""Newly empty buffer work space should not be yieldable."""
with tempfile.NamedTemporaryFile(delete=False) as t:
with io.open(t.name, mode="rb") as fp:
b = BufferWorkSpace(fp, chunk_size=io.DEFAULT_BUFFER_SIZE)
r = b.yieldable()
self.assertFalse(r)
os.unlink(t.name)
def test_return_line_contract_violation(self):
"""BufferWorkSpace (of a completely empty file) would result in contract violation for return_line."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 0
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
with self.assertRaises(AssertionError):
b.return_line()
def test_has_returned_every_line_empty_file(self):
"""With empty file (a degenerate case), it is expected to have returned everything."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 0
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
r = b.has_returned_every_line()
self.assertTrue(r)
def test_add_to_empty_buffer_work_space(self):
"""Test reading last 3 bytes from a 1024 byte file."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.add_to_buffer(content=b"aaa", read_position=1021)
self.assertEqual(b.read_buffer, b"aaa")
self.assertEqual(b.read_position, 1021)
def test_has_returned_every_line_with_not_fully_read_in_buffer_space(self):
"""With BufferWorkSpace that has not fully read in, it definitely has not returned everything.
Note that: not fully read in is represented by read_position != 0
"""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 1
r = b.has_returned_every_line()
self.assertFalse(r)
def test_return_line_with_buffer_space_with_two_new_lines(self):
"""With two new lines as its sole contents, the buffer space is expected to return b''."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
for n in new_lines_bytes:
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 1024 - (len(n) * 2)
b.read_buffer = n * 2
expected_result = b""
r = b.return_line()
self.assertEqual(r, expected_result)
def test_yieldable_for_buffer_space_with_two_new_lines(self):
"""Buffer work space with a two new lines are yieldable."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
for n in new_lines_bytes:
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 1024 - (len(n) * 2)
b.read_buffer = n * 2
expected_result = True
r = b.yieldable()
self.assertEqual(r, expected_result)
def test_yieldable_for_unexhausted_buffer_space_with_single_new_line(self):
"""Buffer work space with a single new line (with read_position > 0) is not be yieldable."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
for n in new_lines_bytes:
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 1024 - len(n)
b.read_buffer = n
expected_result = False
r = b.yieldable()
self.assertEqual(r, expected_result)
def test_return_line_with_buffer_space_with_fully_read_in_contents_at_its_last_line(
self):
"""With some bytestrings in between 2 new lines, expect to have the bytestrings in the middle."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
for n in new_lines_bytes:
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 0
b.read_buffer = b"LastLineYay"
expected_result = b"LastLineYay"
r = b.return_line()
self.assertEqual(r, expected_result)
def test_return_line_with_buffer_space_with_some_contents_between_two_new_lines(
self):
"""With some bytestrings in between 2 new lines, expect to have the bytestrings in the middle."""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
for n in new_lines_bytes:
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 1024 - (len(n) * 2)
b.read_buffer = n + b"Something" + n
expected_result = b"Something"
r = b.return_line()
self.assertEqual(r, expected_result)
def test_has_returned_every_line_with_fully_read_in_and_processed_buffer_space(
self):
"""BufferWorkSpace that has been fully read in and fully processed has not returned everything.
Note: not fully read in and some unprocessed buffer is represented by read_position = 0 and read_buffer = None
"""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 0
b.read_buffer = None
r = b.has_returned_every_line()
self.assertTrue(r)
def test_yieldable_for_fully_read_and_returned_contents_in_buffer_space(
self):
"""BufferWorkSpace that has been fully read in and returned contents is not yieldable.
Note: fully read-in and returned is represented by read_position = 0, read_buffer is None.
"""
with patch("file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
for n in new_lines_bytes:
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 0
b.read_buffer = None
r = b.yieldable()
self.assertFalse(r)
def test_yieldable_for_fully_read_with_unreturned_contents_in_buffer_space(
self,
):
"""Buffer work space that has been fully read in and unreturned contents is yieldable.
Note: fully read in and unreturned contents is represented by read_position = 0 and read_buffer is not None.
"""
with patch(
"file_read_backwards.buffer_work_space._get_file_size"
) as _get_file_size_mock:
fp_mock = Mock()
_get_file_size_mock.return_value = 1024
for n in new_lines_bytes:
b = BufferWorkSpace(fp_mock, chunk_size=io.DEFAULT_BUFFER_SIZE)
b.read_position = 0
b.read_buffer = b""
expected_result = True
r = b.yieldable()
self.assertEqual(r, expected_result)
