def test_tell_and_seek_boundaries(self):
# Test to ensure ReadFileChunk behaves the same as the
# Python standard library around seeking and reading out
# of bounds in a file object.
data = b'abcdefghij12345678klmnopqrst'
start_pos = 10
chunk_size = 8
# Create test file
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(data)
# ReadFileChunk should be a substring of only numbers
file_objects = [
ReadFileChunk.from_filename(filename,
start_byte=start_pos,
chunk_size=chunk_size)
]
# Uncomment next line to validate we match Python's io.BytesIO
# file_objects.append(io.BytesIO(data[start_pos:start_pos+chunk_size]))
for obj in file_objects:
self._assert_whence_start_behavior(obj)
self._assert_whence_end_behavior(obj)
self._assert_whence_relative_behavior(obj)
self._assert_boundary_behavior(obj)
def test_file_chunk_supports_context_manager(self):
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(b'abc')
with ReadFileChunk.from_filename(filename, start_byte=0,
chunk_size=2) as chunk:
val = chunk.read()
self.assertEqual(val, b'ab')
def test_callback_is_invoked_on_read(self):
chunk = ReadFileChunk.from_filename(
self.filename, start_byte=0, chunk_size=3,
callbacks=[self.callback])
chunk.read(1)
chunk.read(1)
chunk.read(1)
self.assertEqual(self.amounts_seen, [1, 1, 1])
def test_iter_is_always_empty(self):
# This tests the workaround for the httplib bug (see
# the source for more info).
filename = os.path.join(self.tempdir, 'foo')
open(filename, 'wb').close()
chunk = ReadFileChunk.from_filename(
filename, start_byte=0, chunk_size=10)
self.assertEqual(list(chunk), [])
def test_read_entire_chunk(self):
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(b'onetwothreefourfivesixseveneightnineten')
chunk = ReadFileChunk.from_filename(
filename, start_byte=0, chunk_size=3)
self.assertEqual(chunk.read(), b'one')
self.assertEqual(chunk.read(), b'')
def test_callback_can_be_disabled(self):
chunk = ReadFileChunk.from_filename(
self.filename, start_byte=0, chunk_size=3,
callbacks=[self.callback])
chunk.disable_callback()
# Now reading from the ReadFileChunk should not invoke
# the callback.
chunk.read()
self.assertEqual(self.amounts_seen, [])
def test_file_chunk_supports_context_manager(self):
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(b'abc')
with ReadFileChunk.from_filename(filename,
start_byte=0,
chunk_size=2) as chunk:
val = chunk.read()
self.assertEqual(val, b'ab')
def test_reset_stream_emulation(self):
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(b'onetwothreefourfivesixseveneightnineten')
chunk = ReadFileChunk.from_filename(
filename, start_byte=11, chunk_size=4)
self.assertEqual(chunk.read(), b'four')
chunk.seek(0)
self.assertEqual(chunk.read(), b'four')
def test_callback_will_also_be_triggered_by_seek(self):
chunk = ReadFileChunk.from_filename(
self.filename, start_byte=0, chunk_size=3,
callbacks=[self.callback])
chunk.read(2)
chunk.seek(0)
chunk.read(2)
chunk.seek(1)
chunk.read(2)
self.assertEqual(self.amounts_seen, [2, -2, 2, -1, 2])
def test_all_callbacks_invoked_on_read(self):
chunk = ReadFileChunk.from_filename(
self.filename, start_byte=0, chunk_size=3,
callbacks=[self.callback, self.callback])
chunk.read(1)
chunk.read(1)
chunk.read(1)
# The list should be twice as long because there are two callbacks
# recording the amount read.
self.assertEqual(self.amounts_seen, [1, 1, 1, 1, 1, 1])
def test_signal_transferring(self):
chunk = ReadFileChunk.from_filename(self.filename,
start_byte=0,
chunk_size=3,
callbacks=[self.callback])
chunk.signal_not_transferring()
chunk.read(1)
self.assertEqual(self.amounts_seen, [])
chunk.signal_transferring()
chunk.read(1)
self.assertEqual(self.amounts_seen, [1])
def test_tell_and_seek(self):
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(b'onetwothreefourfivesixseveneightnineten')
chunk = ReadFileChunk.from_filename(
filename, start_byte=36, chunk_size=100000)
self.assertEqual(chunk.tell(), 0)
self.assertEqual(chunk.read(), b'ten')
self.assertEqual(chunk.tell(), 3)
chunk.seek(0)
self.assertEqual(chunk.tell(), 0)
def test_read_with_amount_size(self):
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(b'onetwothreefourfivesixseveneightnineten')
chunk = ReadFileChunk.from_filename(
filename, start_byte=11, chunk_size=4)
self.assertEqual(chunk.read(1), b'f')
self.assertEqual(chunk.read(1), b'o')
self.assertEqual(chunk.read(1), b'u')
self.assertEqual(chunk.read(1), b'r')
self.assertEqual(chunk.read(1), b'')
def test_callback_triggered_by_out_of_bound_seeks(self):
data = b'abcdefghij1234567890klmnopqr'
# Create test file
filename = os.path.join(self.tempdir, 'foo')
with open(filename, 'wb') as f:
f.write(data)
chunk = ReadFileChunk.from_filename(filename,
start_byte=10,
chunk_size=10,
callbacks=[self.callback])
# Seek calls that generate "0" progress are skipped by
# invoke_progress_callbacks and won't appear in the list.
expected_callback_prog = [10, -5, 5, -1, 1, -1, 1, -5, 5, -10]
self._assert_out_of_bound_start_seek(chunk, expected_callback_prog)
self._assert_out_of_bound_relative_seek(chunk, expected_callback_prog)
self._assert_out_of_bound_end_seek(chunk, expected_callback_prog)
def open_file_chunk_reader(self, filename, start_byte, size, callbacks):
return ReadFileChunk.from_filename(filename,
start_byte,
size,
callbacks,
enable_callbacks=True)
