def test_write_mode(self):
'''
'w': open for writing, truncting the file first. Create if the file doesn't exist.
Demonstrate that unable to read, can write to and truncate an existing file,
can create a file if it doesn't exist, error on an existing file that doesn't have write permission,
error on missing directory permission (including on the directory tree)
'''
# 1. check if opening a non-existing file will first create a such file
# generate a 15-character-long letters-digits-mixed string as filename,
# chance that it already exists is close to zero.
random.seed(8) # I also like 8
filename = '/' + ''.join(
random.choices(string.ascii_letters + string.digits, k=15))
f = sfs.open(filename, 'w')
self.assertTrue(os.path.isfile('/efs' + filename))
# 2. check if write-only
new_f = open('/efs/test.txt', 'w+')
new_f.write('You cannot read it')
new_f.close()
f = sfs.open('/test.txt', 'w')
self.assertRaises(io.UnsupportedOperation, f.read, 1)
# 3. write to an empty file.
new_f = open('/efs' + filename,
'w+') # this line truncates the file, makes it empty
new_f.close()
content = 'Writing to an empty file'
f = sfs.open(filename, 'w')
n = f.write(content)
self.assertEqual(
n, len(content)) # check sfs.write return value, # bytes written
new_f = open('/efs' + filename, 'r')
self.assertEqual(new_f.read(len(content)),
content) # check written content
new_f.close()
# 4. write to a non-empty existing file, should truncate the file first
filename = '/test_write.txt'
new_f = open('/efs' + filename, 'w+')
old_content = 'This is a test file'
n = new_f.write(old_content)
self.assertEqual(n,
len(old_content)) # this ensure the file is not empty
new_f.close()
f = sfs.open(filename, 'w')
new_content = 'Writing to a non-empty file'
n = f.write(new_content)
self.assertEqual(n, len(new_content))
new_f = open('/efs' + filename, 'r')
self.assertEqual(new_f.read(len(new_content)), new_content)
new_f.close()
def test_read_mode(self):
'''
'r': open for reading text, synonym of 'rt' (default).
Demonstrate that can read, unable to write, error on file does not exist,
error on missing read permission (including directory tree)
'''
# 1. check if error on a non-existing file
# generate a 15-character-long letters-digits-mixed string as filename,
# chance that it already exists is close to zero.
# Open a file with such filename should raise a FileNotFoundError exception
random.seed(6) # I like 6
filename = '/' + ''.join(
random.choices(string.ascii_letters + string.digits, k=15))
self.assertRaises(FileNotFoundError, sfs.open, filename, "r")
# 2. check if can read an existing file
new_f = open("/efs/test.txt",
'w+') # make sure to run this script as ROOT
content = "This is a test file."
new_f.write(content)
new_f.close()
f = sfs.open('/test.txt', 'r')
self.assertEqual(f.read(len(content)).decode('utf-8'), content)
# 3. check if cannot write
self.assertRaises(io.UnsupportedOperation, f.write, "1")
# 4. check if error on missing read permission
# TODO: currently sfs.open DOES NOT raise an exception
new_f = open("/efs/no_read_perm.txt", 'w+')
new_f.close()
os.chmod("/efs/no_read_perm.txt", 0o000)
self.assertRaises(PermissionError, sfs.open, "/no_read_perm.txt", 'r')
def test_sequential_read(file_name, num_blocks, block_length):
"""Read NUM_BLOCKS blocks sequentially."""
print("starting test sequential read\n")
with sfs.open(file_name, "r") as f:
start_time = time.time()
for _ in range(num_blocks):
f.read(block_length)
end_time = time.time()
time_delta = end_time - start_time
print_stats(num_blocks, block_length, time_delta)
def test_sequential_write(file_name, num_blocks, block_length):
"""Write NUM_BLOCKS block sequentially."""
block_content = ''.join(
random.choice(string.ascii_uppercase + string.digits) for _ in range(block_length))
print("starting test sequential write\n")
with sfs.open(file_name, "a") as f:
start_time = time.time()
for _ in range(num_blocks):
f.write(block_content.encode('utf-8'))
end_time = time.time()
time_delta = end_time - start_time
print_stats(num_blocks, block_length, time_delta)
def test_random_read(file_name, num_blocks, block_length):
"""Read NUM_BLOCKS blocks in a random order with repeition."""
print("starting test random read\n")
with sfs.open(file_name, "r") as f:
start_time = time.time()
for _ in range(num_blocks):
random_block_index = random.randint(0, num_blocks)
byte_offset = random_block_index * block_length
f.seek(byte_offset, 0)
f.read(block_length)
end_time = time.time()
time_delta = end_time - start_time
print_stats(num_blocks, block_length, time_delta)
def test_random_write(file_name, num_blocks, block_length):
"""Write NUM_BLOCKS blocks in a random order with repeition with random content."""
print("starting test random write\n")
block_content = ''.join(
random.choice(string.ascii_uppercase + string.digits) for _ in range(block_length))
with sfs.open(file_name, "w") as f:
start_time = time.time()
for _ in range(num_blocks):
random_block_index = random.randint(0, num_blocks)
byte_offset = random_block_index * block_length
f.seek(byte_offset, 0)
f.write(block_content.encode('utf-8'))
end_time = time.time()
time_delta = end_time - start_time
print_stats(num_blocks, block_length, time_delta)