license & copyright notices; docstrings for each module; extended readme

COPYING

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+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
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+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

COPYING.LESSER

@@ -0,0 +1,165 @@
+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
+  As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
+  "The Library" refers to a covered work governed by this License,
+other than an Application or a Combined Work as defined below.
+
+  An "Application" is any work that makes use of an interface provided
+by the Library, but which is not otherwise based on the Library.
+Defining a subclass of a class defined by the Library is deemed a mode
+of using an interface provided by the Library.
+
+  A "Combined Work" is a work produced by combining or linking an
+Application with the Library.  The particular version of the Library
+with which the Combined Work was made is also called the "Linked
+Version".
+
+  The "Minimal Corresponding Source" for a Combined Work means the
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+for portions of the Combined Work that, considered in isolation, are
+based on the Application, and not on the Linked Version.
+
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+object code and/or source code for the Application, including any data
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+Application, but excluding the System Libraries of the Combined Work.
+
+  1. Exception to Section 3 of the GNU GPL.
+
+  You may convey a covered work under sections 3 and 4 of this License
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+
+  2. Conveying Modified Versions.
+
+  If you modify a copy of the Library, and, in your modifications, a
+facility refers to a function or data to be supplied by an Application
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+version:
+
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+   function or data, the facility still operates, and performs
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+
+   b) under the GNU GPL, with none of the additional permissions of
+   this License applicable to that copy.
+
+  3. Object Code Incorporating Material from Library Header Files.
+
+  The object code form of an Application may incorporate material from
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+(ten or fewer lines in length), you do both of the following:
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+   a) Give prominent notice with each copy of the object code that the
+   Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the object code with a copy of the GNU GPL and this license
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+
+  4. Combined Works.
+
+  You may convey a Combined Work under terms of your choice that,
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+the following:
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+   a) Give prominent notice with each copy of the Combined Work that
+   the Library is used in it and that the Library and its use are
+   covered by this License.
+
+   b) Accompany the Combined Work with a copy of the GNU GPL and this license
+   document.
+
+   c) For a Combined Work that displays copyright notices during
+   execution, include the copyright notice for the Library among
+   these notices, as well as a reference directing the user to the
+   copies of the GNU GPL and this license document.
+
+   d) Do one of the following:
+
+       0) Convey the Minimal Corresponding Source under the terms of this
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+       suitable for, and under terms that permit, the user to
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+       manner specified by section 6 of the GNU GPL for conveying
+       Corresponding Source.
+
+       1) Use a suitable shared library mechanism for linking with the
+       Library.  A suitable mechanism is one that (a) uses at run time
+       a copy of the Library already present on the user's computer
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+       of the Library that is interface-compatible with the Linked
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+
+   e) Provide Installation Information, but only if you would otherwise
+   be required to provide such information under section 6 of the
+   GNU GPL, and only to the extent that such information is
+   necessary to install and execute a modified version of the
+   Combined Work produced by recombining or relinking the
+   Application with a modified version of the Linked Version. (If
+   you use option 4d0, the Installation Information must accompany
+   the Minimal Corresponding Source and Corresponding Application
+   Code. If you use option 4d1, you must provide the Installation
+   Information in the manner specified by section 6 of the GNU GPL
+   for conveying Corresponding Source.)
+
+  5. Combined Libraries.
+
+  You may place library facilities that are a work based on the
+Library side by side in a single library together with other library
+facilities that are not Applications and are not covered by this
+License, and convey such a combined library under terms of your
+choice, if you do both of the following:
+
+   a) Accompany the combined library with a copy of the same work based
+   on the Library, uncombined with any other library facilities,
+   conveyed under the terms of this License.
+
+   b) Give prominent notice with the combined library that part of it
+   is a work based on the Library, and explaining where to find the
+   accompanying uncombined form of the same work.
+
+  6. Revised Versions of the GNU Lesser General Public License.
+
+  The Free Software Foundation may publish revised and/or new versions
+of the GNU Lesser General Public License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns.
+
+  Each version is given a distinguishing version number. If the
+Library as you received it specifies that a certain numbered version
+of the GNU Lesser General Public License "or any later version"
+applies to it, you have the option of following the terms and
+conditions either of that published version or of any later version
+published by the Free Software Foundation. If the Library as you
+received it does not specify a version number of the GNU Lesser
+General Public License, you may choose any version of the GNU Lesser
+General Public License ever published by the Free Software Foundation.
+
+  If the Library as you received it specifies that a proxy can decide
+whether future versions of the GNU Lesser General Public License shall
+apply, that proxy's public statement of acceptance of any version is
+permanent authorization for you to choose that version for the
+Library.

README.md

@@ -1,19 +1,61 @@
 # asyncio-taskpool
 
-Dynamically manage pools of asyncio tasks
+**Dynamically manage pools of asyncio tasks**
+
+## Summary
+
+A task pool is an object with a simple interface for aggregating and dynamically managing asynchronous tasks.
+
+With an interface that is intentionally similar to the [`multiprocessing.Pool`](https://docs.python.org/3/library/multiprocessing.html#module-multiprocessing.pool) class from the standard library, the `TaskPool` provides you such methods as `apply`, `map`, and `starmap` to execute coroutines concurrently as [`asyncio.Task`](https://docs.python.org/3/library/asyncio-task.html#task-object) objects. There is no limitation imposed on what kind of tasks can be run or in what combination, when new ones can be added, or when they can be cancelled.
+
+For a more streamlined use-case, the `SimpleTaskPool` provides an even more intuitive and simple interface at the cost of flexibility.
+
+If you need control over a task pool at runtime, you can launch an asynchronous `ControlServer` to be able to interface with the pool from an outside process or via a network, and stop/start tasks within the pool as you wish.
 
 ## Usage
 
-See [USAGE.md](usage/USAGE.md)
+Generally speaking, a task is added to a pool by providing it with a coroutine function reference as well as the arguments for that function. Here is what that could look like:
+```python
+from asyncio_taskpool import SimpleTaskPool
+...
+async def work(foo, bar): ...
+...
+async def main():
+    pool = SimpleTaskPool(work, args=('xyz', 420))
+    await pool.start(5)
+    ...
+    pool.stop(3)
+    ...
+    pool.lock()
+    await pool.gather()
+    ...
+```
+
+Since one of the main goals of `asyncio-taskpool` is to be able to start/stop tasks dynamically or "on-the-fly", _most_ of the associated methods are non-blocking _most_ of the time. A notable exception is the `gather` method for awaiting the return of all tasks in the pool. (It is essentially a glorified wrapper around the [`asyncio.gather`](https://docs.python.org/3/library/asyncio-task.html#asyncio.gather) function.)
+
+For working and fully documented demo scripts see [USAGE.md](usage/USAGE.md).
 
 ## Installation
 
-`pip install asyncio-taskpool`
+```shell
+pip install asyncio-taskpool
+```
 
 ## Dependencies
 
 Python Version 3.8+, tested on Linux
 
-## Building from source
+## Testing
 
-Run `python -m build`
+Install `asyncio-taskpool[dev]` dependencies or just manually install `coverage` with `pip`. 
+Execute the [`./coverage.sh`](coverage.sh) shell script to run all unit tests and receive the coverage report.
+
+## License
+
+`asyncio-taskpool` is licensed under the **GNU LGPL version 3.0** specifically.
+
+The full license texts for the [GNU GPLv3.0](COPYING) and the [GNU LGPLv3.0](COPYING.LESSER) are included in this repository. If not, see https://www.gnu.org/licenses/.
+
+## Copyright
+
+© 2022 Daniil Fajnberg

setup.cfg

@@ -1,17 +1,25 @@
 [metadata]
 name = asyncio-taskpool
-version = 0.1.4
+version = 0.2.1
 author = Daniil Fajnberg
 author_email = mail@daniil.fajnberg.de
 description = Dynamically manage pools of asyncio tasks
 long_description = file: README.md
 long_description_content_type = text/markdown
+keywords = asyncio, concurrency, tasks, coroutines, asynchronous, server
 url = https://git.fajnberg.de/daniil/asyncio-taskpool
 project_urls =
     Bug Tracker = https://git.fajnberg.de/daniil/asyncio-taskpool/issues
 classifiers =
+    Development Status :: 3 - Alpha
     Programming Language :: Python :: 3
     Operating System :: OS Independent
+    License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3)
+    Intended Audience :: Developers
+    Intended Audience :: System Administrators
+    Framework :: AsyncIO
+    Topic :: Software Development :: Libraries
+    Topic :: Software Development :: Libraries :: Python Modules
 
 [options]
 package_dir =

src/asyncio_taskpool/__init__.py

@@ -1,2 +1,23 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Brings the main classes up to package level for import convenience.
+"""
+
+
 from .pool import TaskPool, SimpleTaskPool
 from .server import UnixControlServer

src/asyncio_taskpool/__main__.py

@@ -1,3 +1,24 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+CLI client entry point.
+"""
+
+
 import sys
 from argparse import ArgumentParser
 from asyncio import run

src/asyncio_taskpool/client.py

@@ -1,3 +1,24 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Classes of control clients for a simply interface to a task pool control server.
+"""
+
+
 import sys
 from abc import ABC, abstractmethod
 from asyncio.streams import StreamReader, StreamWriter, open_unix_connection

src/asyncio_taskpool/constants.py

@@ -1,8 +1,29 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Constants used by more than one module in the package.
+"""
+
+
 PACKAGE_NAME = 'asyncio_taskpool'
 MSG_BYTES = 1024
 CMD_START = 'start'
 CMD_STOP = 'stop'
 CMD_STOP_ALL = 'stop_all'
-CMD_SIZE = 'size'
+CMD_NUM_RUNNING = 'num_running'
 CMD_FUNC = 'func'
 CLIENT_EXIT = 'exit'

src/asyncio_taskpool/exceptions.py

@@ -1,8 +1,29 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Custom exception classes used in various modules.
+"""
+
+
 class PoolException(Exception):
     pass
 
 
-class PoolIsClosed(PoolException):
+class PoolIsLocked(PoolException):
     pass
 
 
@@ -22,7 +43,7 @@ class InvalidTaskID(PoolException):
     pass
 
 
-class PoolStillOpen(PoolException):
+class PoolStillUnlocked(PoolException):
     pass
 
 

src/asyncio_taskpool/helpers.py

@@ -1,3 +1,24 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Miscellaneous helper functions.
+"""
+
+
 from asyncio.coroutines import iscoroutinefunction
 from asyncio.queues import Queue
 from typing import Any, Optional

src/asyncio_taskpool/pool.py

@@ -1,3 +1,36 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+This module contains the definitions of the task pool classes.
+
+A task pool is an object with a simple interface for aggregating and dynamically managing asynchronous tasks.
+Generally speaking, a task is added to a pool by providing it with a coroutine function reference as well as the 
+arguments for that function.
+
+The `BaseTaskPool` class is a parent class and not intended for direct use.
+The `TaskPool` and `SimpleTaskPool` are subclasses intended for direct use.
+While the former allows for heterogeneous collections of tasks that can be entirely unrelated to one another, the 
+latter requires a preemptive decision about the function **and** its arguments upon initialization and only allows
+to dynamically control the **number** of tasks running at any point in time.
+
+For further details about the classes check their respective docstrings.
+"""
+
+
 import logging
 from asyncio import gather
 from asyncio.coroutines import iscoroutine, iscoroutinefunction
@@ -31,7 +64,7 @@ class BaseTaskPool:
         """Initializes the necessary internal attributes and adds the new pool to the general pools list."""
         self._enough_room: Semaphore = Semaphore()
         self.pool_size = pool_size
-        self._open: bool = True
+        self._locked: bool = False
         self._counter: int = 0
         self._running: Dict[int, Task] = {}
         self._cancelled: Dict[int, Task] = {}
@@ -71,9 +104,21 @@ class BaseTaskPool:
         self._pool_size = value
 
     @property
-    def is_open(self) -> bool:
+    def is_locked(self) -> bool:
-        """Returns `True` if more the pool has not been closed yet."""
+        """Returns `True` if more the pool has been locked (see below)."""
-        return self._open
+        return self._locked
+
+    def lock(self) -> None:
+        """Disallows any more tasks to be started in the pool."""
+        if not self._locked:
+            self._locked = True
+            log.info("%s is locked!", str(self))
+
+    def unlock(self) -> None:
+        """Allows new tasks to be started in the pool."""
+        if self._locked:
+            self._locked = False
+            log.info("%s was unlocked.", str(self))
 
     @property
     def num_running(self) -> int:
@@ -187,7 +232,7 @@ class BaseTaskPool:
         finally:
             await self._task_ending(task_id, custom_callback=end_callback)
 
-    async def _start_task(self, awaitable: Awaitable, ignore_closed: bool = False, end_callback: EndCallbackT = None,
+    async def _start_task(self, awaitable: Awaitable, ignore_lock: bool = False, end_callback: EndCallbackT = None,
                           cancel_callback: CancelCallbackT = None) -> int:
         """
         Starts a coroutine as a new task in the pool.
@@ -197,8 +242,8 @@ class BaseTaskPool:
         Args:
             awaitable:
                 The actual coroutine to be run within the task pool.
-            ignore_closed (optional):
+            ignore_lock (optional):
-                If `True`, even if the pool is closed, the task will still be started.
+                If `True`, even if the pool is locked, the task will still be started.
             end_callback (optional):
                 A callback to execute after the task has ended.
                 It is run with the task's ID as its only positional argument.
@@ -208,12 +253,12 @@ class BaseTaskPool:
 
         Raises:
             `asyncio_taskpool.exceptions.NotCoroutine` if `awaitable` is not a coroutine.
-            `asyncio_taskpool.exceptions.PoolIsClosed` if the pool has been closed and `ignore_closed` is `False`.
+            `asyncio_taskpool.exceptions.PoolIsLocked` if the pool has been locked and `ignore_lock` is `False`.
         """
         if not iscoroutine(awaitable):
             raise exceptions.NotCoroutine(f"Not awaitable: {awaitable}")
-        if not (self.is_open or ignore_closed):
+        if self._locked and not ignore_lock:
-            raise exceptions.PoolIsClosed("Cannot start new tasks")
+            raise exceptions.PoolIsLocked("Cannot start new tasks")
         await self._enough_room.acquire()
         task_id = self._counter
         self._counter += 1
@@ -303,16 +348,11 @@ class BaseTaskPool:
             self._interrupt_flag.clear()
         return results
 
-    def close(self) -> None:
-        """Disallows any more tasks to be started in the pool."""
-        self._open = False
-        log.info("%s is closed!", str(self))
-
     async def gather(self, return_exceptions: bool = False):
         """
         Calls `asyncio.gather` on **all** tasks from the pool, returns their results, and forgets the tasks.
 
-        The `close()` method must have been called prior to this.
+        The `lock()` method must have been called prior to this.
 
         Note that there may be an unknown number of coroutine functions "queued" to be run as tasks.
         This can happen, if for example the `TaskPool.map` method was called with `num_tasks` set to a number smaller
@@ -327,10 +367,10 @@ class BaseTaskPool:
             return_exceptions (optional): Passed directly into `gather`.
 
         Raises:
-            `asyncio_taskpool.exceptions.PoolStillOpen` if the pool has not been closed yet.
+            `asyncio_taskpool.exceptions.PoolStillUnlocked` if the pool has not been locked yet.
         """
-        if self._open:
+        if not self._locked:
-            raise exceptions.PoolStillOpen("Pool must be closed, before tasks can be gathered")
+            raise exceptions.PoolStillUnlocked("Pool must be locked, before tasks can be gathered")
         await gather(*self._before_gathering)
         results = await gather(*self._ended.values(), *self._cancelled.values(), *self._running.values(),
                                return_exceptions=return_exceptions)
@@ -415,7 +455,7 @@ class TaskPool(BaseTaskPool):
 
         Raises:
             `NotCoroutine` if `func` is not a coroutine function.
-            `PoolIsClosed` if the pool has been closed already.
+            `PoolIsLocked` if the pool has been locked already.
         """
         ids = await gather(*(self._apply_one(func, args, kwargs, end_callback, cancel_callback) for _ in range(num)))
         # TODO: for some reason PyCharm wrongly claims that `gather` returns a tuple of exceptions
@@ -438,7 +478,7 @@ class TaskPool(BaseTaskPool):
                 break
             await q.put(arg)  # This blocks as long as the queue is full.
 
-    async def _queue_consumer(self, q: Queue, func: CoroutineFunc, arg_stars: int = 0,
+    async def _queue_consumer(self, q: Queue, first_batch_started: Event, func: CoroutineFunc, arg_stars: int = 0,
                               end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
         """
         Wrapper around the `_start_task()` taking the next element from the arguments queue set up in `_map()`.
@@ -447,6 +487,9 @@ class TaskPool(BaseTaskPool):
         Args:
             q:
                 The queue of function arguments to consume for starting the next task.
+            first_batch_started:
+                The event flag to wait for, before launching the next consumer.
+                It can only set by the `_map()` method, which happens after the first batch of task has been started.
             func:
                 The coroutine function to use for spawning the tasks within the task pool.
             arg_stars (optional):
@@ -465,16 +508,18 @@ class TaskPool(BaseTaskPool):
         try:
             await self._start_task(
                 star_function(func, arg, arg_stars=arg_stars),
-                ignore_closed=True,
+                ignore_lock=True,
-                end_callback=partial(TaskPool._queue_callback, self, q=q, func=func, arg_stars=arg_stars,
+                end_callback=partial(TaskPool._queue_callback, self, q=q, first_batch_started=first_batch_started,
-                                     end_callback=end_callback, cancel_callback=cancel_callback),
+                                     func=func, arg_stars=arg_stars, end_callback=end_callback,
+                                     cancel_callback=cancel_callback),
                 cancel_callback=cancel_callback
             )
         finally:
             q.task_done()
 
-    async def _queue_callback(self, task_id: int, q: Queue, func: CoroutineFunc, arg_stars: int = 0,
+    async def _queue_callback(self, task_id: int, q: Queue, first_batch_started: Event, func: CoroutineFunc,
-                              end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
+                              arg_stars: int = 0, end_callback: EndCallbackT = None,
+                              cancel_callback: CancelCallbackT = None) -> None:
         """
         Wrapper around an end callback function passed into the `_map()` method.
         Triggers the next `_queue_consumer` with the same arguments.
@@ -484,6 +529,9 @@ class TaskPool(BaseTaskPool):
                 The ID of the ending task.
             q:
                 The queue of function arguments to consume for starting the next task.
+            first_batch_started:
+                The event flag to wait for, before launching the next consumer.
+                It can only set by the `_map()` method, which happens after the first batch of task has been started.
             func:
                 The coroutine function to use for spawning the tasks within the task pool.
             arg_stars (optional):
@@ -495,41 +543,52 @@ class TaskPool(BaseTaskPool):
                 The callback that was specified to execute after cancellation of the task (and the next one).
                 It is run with the `task_id` as its only positional argument.
         """
-        await self._queue_consumer(q, func, arg_stars, end_callback=end_callback, cancel_callback=cancel_callback)
+        await first_batch_started.wait()
+        await self._queue_consumer(q, first_batch_started, func, arg_stars,
+                                   end_callback=end_callback, cancel_callback=cancel_callback)
         await execute_optional(end_callback, args=(task_id,))
 
-    def _fill_args_queue(self, q: Queue, args_iter: ArgsT, num_tasks: int) -> None:
+    def _set_up_args_queue(self, args_iter: ArgsT, num_tasks: int) -> Queue:
         """
         Helper function for `_map()`.
-        Takes the iterable of function arguments `args_iter` and adds up to `num_tasks` to the arguments queue `q`.
+        Takes the iterable of function arguments `args_iter` and adds up to `num_tasks` to a new `asyncio.Queue`.
+        The queue's `join()` method is added to the pool's `_before_gathering` list and the queue is returned.
 
-        If the iterable contains less than `num_tasks` elements, nothing else happens.
+        If the iterable contains less than `num_tasks` elements, nothing else happens; otherwise the `_queue_producer`
-        Otherwise the `_queue_producer` is started with the arguments queue and and iterator of the remaining arguments.
+        is started as a separate task with the arguments queue and and iterator of the remaining arguments.
 
         Args:
-            q:
-                The (empty) new `asyncio.Queue` to hold the function arguments passed as `args_iter`.
             args_iter:
                 The iterable of function arguments passed into `_map()` to use for creating the new tasks.
             num_tasks:
                 The maximum number of the new tasks to run concurrently that was passed into `_map()`.
+
+        Returns:
+            The newly created and filled arguments queue for spawning new tasks.
         """
+        # Setting the `maxsize` of the queue to `num_tasks` will ensure that no more than `num_tasks` tasks will run
+        # concurrently because the size of the queue is what will determine the number of immediately started tasks in
+        # the `_map()` method and each of those will only ever start (at most) one other task upon ending.
+        args_queue = Queue(maxsize=num_tasks)
+        self._before_gathering.append(join_queue(args_queue))
         args_iter = iter(args_iter)
         try:
             # Here we guarantee that the queue will contain as many arguments as needed for starting the first batch of
             # tasks, which will be at most `num_tasks` (meaning the queue will be full).
             for i in range(num_tasks):
-                q.put_nowait(next(args_iter))
+                args_queue.put_nowait(next(args_iter))
         except StopIteration:
             # If we get here, this means that the number of elements in the arguments iterator was less than the
-            # specified `num_tasks`. Thus, the number of tasks to start immediately will be the size of the queue.
+            # specified `num_tasks`. Still, the number of tasks to start immediately will be the size of the queue.
             # The `_queue_producer` won't be necessary, since we already put all the elements in the queue.
-            return
+            pass
-        # There may be more elements in the arguments iterator, so we need the `_queue_producer`.
+        else:
-        # It will have exclusive access to the `args_iter` from now on.
+            # There may be more elements in the arguments iterator, so we need the `_queue_producer`.
-        # If the queue is full already, it will wait until one of the tasks in the first batch ends, before putting
+            # It will have exclusive access to the `args_iter` from now on.
-        # the next item in it.
+            # Since the queue is full already, it will wait until one of the tasks in the first batch ends,
-        create_task(self._queue_producer(q, args_iter))
+            # before putting the next item in it.
+            create_task(self._queue_producer(args_queue, args_iter))
+        return args_queue
 
     async def _map(self, func: CoroutineFunc, args_iter: ArgsT, arg_stars: int = 0, num_tasks: int = 1,
                    end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
@@ -542,7 +601,6 @@ class TaskPool(BaseTaskPool):
         This method blocks, **only if** there is not enough room in the pool for the first batch of new tasks.
 
         It sets up an internal arguments queue which is continuously filled while consuming the arguments iterable.
-        The queue's `join()` method is added to the pool's `_before_gathering` list.
 
         Args:
             func:
@@ -561,17 +619,23 @@ class TaskPool(BaseTaskPool):
                 It is run with the task's ID as its only positional argument.
 
         Raises:
-            `asyncio_taskpool.exceptions.PoolIsClosed` if the pool has been closed.
+            `asyncio_taskpool.exceptions.PoolIsLocked` if the pool has been locked.
         """
-        if not self.is_open:
+        if not self._locked:
-            raise exceptions.PoolIsClosed("Cannot start new tasks")
+            raise exceptions.PoolIsLocked("Cannot start new tasks")
-        args_queue = Queue(maxsize=num_tasks)
+        args_queue = self._set_up_args_queue(args_iter, num_tasks)
-        self._before_gathering.append(join_queue(args_queue))
+        # We need a flag to ensure that starting all tasks from the first batch here will not be blocked by the
-        self._fill_args_queue(args_queue, args_iter, num_tasks)
+        # `_queue_callback` triggered by one or more of them.
+        # This could happen, e.g. if the pool has just enough room for one more task, but the queue here contains more
+        # than one element, and the pool remains full until after the first task of the first batch ends. Then the
+        # callback might trigger the next `_queue_consumer` before this method can, which will keep it blocked.
+        first_batch_started = Event()
         for _ in range(args_queue.qsize()):
             # This is where blocking can occur, if the pool is full.
-            await self._queue_consumer(args_queue, func,
+            await self._queue_consumer(args_queue, first_batch_started, func,
                                        arg_stars=arg_stars, end_callback=end_callback, cancel_callback=cancel_callback)
+        # Now the callbacks can immediately trigger more tasks.
+        first_batch_started.set()
 
     async def map(self, func: CoroutineFunc, arg_iter: ArgsT, num_tasks: int = 1,
                   end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
@@ -604,7 +668,7 @@ class TaskPool(BaseTaskPool):
                 It is run with the task's ID as its only positional argument.
 
         Raises:
-            `PoolIsClosed` if the pool has been closed.
+            `PoolIsLocked` if the pool has been locked.
             `NotCoroutine` if `func` is not a coroutine function.
         """
         await self._map(func, arg_iter, arg_stars=0, num_tasks=num_tasks,
@@ -632,9 +696,45 @@ class TaskPool(BaseTaskPool):
 
 
 class SimpleTaskPool(BaseTaskPool):
+    """
+    Simplified task pool class.
+
+    A `SimpleTaskPool` instance can manage an arbitrary number of concurrent tasks,
+    but they **must** come from a single coroutine function, called with the same arguments.
+
+    The coroutine function and its arguments are defined upon initialization.
+
+    As long as there is room in the pool, more tasks can be added. (By default, there is no pool size limit.)
+    Each task started in the pool receives a unique ID, which can be used to cancel specific tasks at any moment.
+    However, since all tasks come from the same function-arguments-combination, the specificity of the `cancel()` method
+    is probably unnecessary. Instead, a simpler `stop()` method is introduced.
+
+    Adding tasks blocks **only if** the pool is full at that moment.
+    """
+
     def __init__(self, func: CoroutineFunc, args: ArgsT = (), kwargs: KwArgsT = None,
                  end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None,
-                 name: str = None) -> None:
+                 pool_size: int = inf, name: str = None) -> None:
+        """
+
+        Args:
+            func:
+                The function to use for spawning new tasks within the pool.
+            args (optional):
+                The positional arguments to pass into each function call.
+            kwargs (optional):
+                The keyword-arguments to pass into each function call.
+            end_callback (optional):
+                A callback to execute after a task has ended.
+                It is run with the task's ID as its only positional argument.
+            cancel_callback (optional):
+                A callback to execute after cancellation of a task.
+                It is run with the task's ID as its only positional argument.
+            pool_size (optional):
+                The maximum number of tasks allowed to run concurrently in the pool
+            name (optional):
+                An optional name for the pool.
+        """
         if not iscoroutinefunction(func):
             raise exceptions.NotCoroutine(f"Not a coroutine function: {func}")
         self._func: CoroutineFunc = func
@@ -642,32 +742,39 @@ class SimpleTaskPool(BaseTaskPool):
         self._kwargs: KwArgsT = kwargs if kwargs is not None else {}
         self._end_callback: EndCallbackT = end_callback
         self._cancel_callback: CancelCallbackT = cancel_callback
-        super().__init__(name=name)
+        super().__init__(pool_size=pool_size, name=name)
 
     @property
     def func_name(self) -> str:
+        """Returns the name of the coroutine function used in the pool."""
         return self._func.__name__
 
-    @property
-    def size(self) -> int:
-        return self.num_running
-
     async def _start_one(self) -> int:
+        """Starts a single new task within the pool and returns its ID."""
         return await self._start_task(self._func(*self._args, **self._kwargs),
                                       end_callback=self._end_callback, cancel_callback=self._cancel_callback)
 
     async def start(self, num: int = 1) -> List[int]:
-        return [await self._start_one() for _ in range(num)]
+        """Starts `num` new tasks within the pool and returns their IDs as a list."""
+        ids = await gather(*(self._start_one() for _ in range(num)))
+        assert isinstance(ids, list)  # for PyCharm (see above to-do-item)
+        return ids
 
     def stop(self, num: int = 1) -> List[int]:
-        num = min(num, self.size)
+        """
+        Cancels `num` running tasks within the pool and returns their IDs as a list.
+
+        The tasks are canceled in LIFO order, meaning tasks started later will be stopped before those started earlier.
+        If `num` is greater than or equal to the number of currently running tasks, naturally all tasks are cancelled.
+        """
         ids = []
         for i, task_id in enumerate(reversed(self._running)):
             if i >= num:
-                break
+                break  # We got the desired number of task IDs, there may well be more tasks left to keep running
             ids.append(task_id)
         self.cancel(*ids)
         return ids
 
     def stop_all(self) -> List[int]:
-        return self.stop(self.size)
+        """Cancels all running tasks and returns their IDs as a list."""
+        return self.stop(self.num_running)

src/asyncio_taskpool/server.py

@@ -1,3 +1,24 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+This module contains the task pool control server class definitions.
+"""
+
+
 import logging
 from abc import ABC, abstractmethod
 from asyncio import AbstractServer
@@ -63,8 +84,8 @@ class ControlServer(ABC):  # TODO: Implement interface for normal TaskPool insta
         writer.write(str(self._pool.stop_all()).encode())
 
     def _pool_size(self, writer: StreamWriter) -> None:
-        log.debug("%s requests pool size", self.client_class.__name__)
+        log.debug("%s requests number of running tasks", self.client_class.__name__)
-        writer.write(str(self._pool.size).encode())
+        writer.write(str(self._pool.num_running).encode())
 
     def _pool_func(self, writer: StreamWriter) -> None:
         log.debug("%s requests pool function", self.client_class.__name__)
@@ -83,7 +104,7 @@ class ControlServer(ABC):  # TODO: Implement interface for normal TaskPool insta
                 self._stop_tasks(writer, arg)
             elif cmd == constants.CMD_STOP_ALL:
                 self._stop_all_tasks(writer)
-            elif cmd == constants.CMD_SIZE:
+            elif cmd == constants.CMD_NUM_RUNNING:
                 self._pool_size(writer)
             elif cmd == constants.CMD_FUNC:
                 self._pool_func(writer)

src/asyncio_taskpool/types.py

@@ -1,3 +1,24 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Custom type definitions used in various modules.
+"""
+
+
 from asyncio.streams import StreamReader, StreamWriter
 from typing import Any, Awaitable, Callable, Iterable, Mapping, Tuple, TypeVar, Union
 

tests/test_helpers.py

@@ -0,0 +1,88 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Unittests for the `asyncio_taskpool.helpers` module.
+"""
+
+
+from unittest import IsolatedAsyncioTestCase
+from unittest.mock import MagicMock, AsyncMock, NonCallableMagicMock
+
+from asyncio_taskpool import helpers
+
+
+class HelpersTestCase(IsolatedAsyncioTestCase):
+
+    async def test_execute_optional(self):
+        f, args, kwargs = NonCallableMagicMock(), [1, 2], None
+        a = [f, args, kwargs]  # to avoid IDE nagging
+        self.assertIsNone(await helpers.execute_optional(*a))
+
+        expected_output = 'foo'
+        f = MagicMock(return_value=expected_output)
+        output = await helpers.execute_optional(f, args, kwargs)
+        self.assertEqual(expected_output, output)
+        f.assert_called_once_with(*args)
+
+        f.reset_mock()
+
+        kwargs = {'a': 100, 'b': 200}
+        output = await helpers.execute_optional(f, args, kwargs)
+        self.assertEqual(expected_output, output)
+        f.assert_called_once_with(*args, **kwargs)
+
+        f = AsyncMock(return_value=expected_output)
+        output = await helpers.execute_optional(f, args, kwargs)
+        self.assertEqual(expected_output, output)
+        f.assert_awaited_once_with(*args, **kwargs)
+
+    def test_star_function(self):
+        expected_output = 'bar'
+        f = MagicMock(return_value=expected_output)
+        a = (1, 2, 3)
+        stars = 0
+        output = helpers.star_function(f, a, stars)
+        self.assertEqual(expected_output, output)
+        f.assert_called_once_with(a)
+
+        f.reset_mock()
+
+        stars = 1
+        output = helpers.star_function(f, a, stars)
+        self.assertEqual(expected_output, output)
+        f.assert_called_once_with(*a)
+
+        f.reset_mock()
+
+        a = {'a': 1, 'b': 2}
+        stars = 2
+        output = helpers.star_function(f, a, stars)
+        self.assertEqual(expected_output, output)
+        f.assert_called_once_with(**a)
+
+        with self.assertRaises(ValueError):
+            helpers.star_function(f, a, 3)
+        with self.assertRaises(ValueError):
+            helpers.star_function(f, a, -1)
+        with self.assertRaises(ValueError):
+            helpers.star_function(f, a, 123456789)
+
+    async def test_join_queue(self):
+        mock_join = AsyncMock()
+        mock_queue = MagicMock(join=mock_join)
+        self.assertIsNone(await helpers.join_queue(mock_queue))
+        mock_join.assert_awaited_once_with()

tests/test_pool.py

@@ -1,7 +1,30 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Unittests for the `asyncio_taskpool.pool` module.
+"""
+
+
 import asyncio
 from asyncio.exceptions import CancelledError
+from asyncio.queues import Queue
 from unittest import IsolatedAsyncioTestCase
 from unittest.mock import PropertyMock, MagicMock, AsyncMock, patch, call
+from typing import Type
 
 from asyncio_taskpool import pool, exceptions
 
@@ -14,7 +37,12 @@ class TestException(Exception):
     pass
 
 
-class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
+class CommonTestCase(IsolatedAsyncioTestCase):
+    TEST_CLASS: Type[pool.BaseTaskPool] = pool.BaseTaskPool
+    TEST_POOL_SIZE: int = 420
+    TEST_POOL_NAME: str = 'test123'
+
+    task_pool: pool.BaseTaskPool
     log_lvl: int
 
     @classmethod
@@ -26,39 +54,42 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
     def tearDownClass(cls) -> None:
         pool.log.setLevel(cls.log_lvl)
 
-    def setUp(self) -> None:
+    def get_task_pool_init_params(self) -> dict:
-        self._pools = getattr(pool.BaseTaskPool, '_pools')
+        return {'pool_size': self.TEST_POOL_SIZE, 'name': self.TEST_POOL_NAME}
 
-        # These three methods are called during initialization, so we mock them by default during setup
+    def setUp(self) -> None:
-        self._add_pool_patcher = patch.object(pool.BaseTaskPool, '_add_pool')
+        self._pools = self.TEST_CLASS._pools
-        self.pool_size_patcher = patch.object(pool.BaseTaskPool, 'pool_size', new_callable=PropertyMock)
+        # These three methods are called during initialization, so we mock them by default during setup:
-        self.__str___patcher = patch.object(pool.BaseTaskPool, '__str__')
+        self._add_pool_patcher = patch.object(self.TEST_CLASS, '_add_pool')
+        self.pool_size_patcher = patch.object(self.TEST_CLASS, 'pool_size', new_callable=PropertyMock)
+        self.dunder_str_patcher = patch.object(self.TEST_CLASS, '__str__')
         self.mock__add_pool = self._add_pool_patcher.start()
         self.mock_pool_size = self.pool_size_patcher.start()
-        self.mock___str__ = self.__str___patcher.start()
+        self.mock___str__ = self.dunder_str_patcher.start()
         self.mock__add_pool.return_value = self.mock_idx = 123
         self.mock___str__.return_value = self.mock_str = 'foobar'
 
-        # Test pool parameters:
+        self.task_pool = self.TEST_CLASS(**self.get_task_pool_init_params())
-        self.test_pool_size, self.test_pool_name = 420, 'test123'
-        self.task_pool = pool.BaseTaskPool(pool_size=self.test_pool_size, name=self.test_pool_name)
 
     def tearDown(self) -> None:
-        setattr(pool.TaskPool, '_pools', self._pools)
+        self.TEST_CLASS._pools.clear()
         self._add_pool_patcher.stop()
         self.pool_size_patcher.stop()
-        self.__str___patcher.stop()
+        self.dunder_str_patcher.stop()
+
+
+class BaseTaskPoolTestCase(CommonTestCase):
 
     def test__add_pool(self):
         self.assertListEqual(EMPTY_LIST, self._pools)
         self._add_pool_patcher.stop()
-        output = pool.TaskPool._add_pool(self.task_pool)
+        output = pool.BaseTaskPool._add_pool(self.task_pool)
         self.assertEqual(0, output)
-        self.assertListEqual([self.task_pool], getattr(pool.TaskPool, '_pools'))
+        self.assertListEqual([self.task_pool], pool.BaseTaskPool._pools)
 
     def test_init(self):
         self.assertIsInstance(self.task_pool._enough_room, asyncio.locks.Semaphore)
-        self.assertTrue(self.task_pool._open)
+        self.assertFalse(self.task_pool._locked)
         self.assertEqual(0, self.task_pool._counter)
         self.assertDictEqual(EMPTY_DICT, self.task_pool._running)
         self.assertDictEqual(EMPTY_DICT, self.task_pool._cancelled)
@@ -66,26 +97,26 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.assertEqual(0, self.task_pool._num_cancelled)
         self.assertEqual(0, self.task_pool._num_ended)
         self.assertEqual(self.mock_idx, self.task_pool._idx)
-        self.assertEqual(self.test_pool_name, self.task_pool._name)
+        self.assertEqual(self.TEST_POOL_NAME, self.task_pool._name)
         self.assertListEqual(self.task_pool._before_gathering, EMPTY_LIST)
         self.assertIsInstance(self.task_pool._interrupt_flag, asyncio.locks.Event)
         self.assertFalse(self.task_pool._interrupt_flag.is_set())
         self.mock__add_pool.assert_called_once_with(self.task_pool)
-        self.mock_pool_size.assert_called_once_with(self.test_pool_size)
+        self.mock_pool_size.assert_called_once_with(self.TEST_POOL_SIZE)
         self.mock___str__.assert_called_once_with()
 
     def test___str__(self):
-        self.__str___patcher.stop()
+        self.dunder_str_patcher.stop()
-        expected_str = f'{pool.BaseTaskPool.__name__}-{self.test_pool_name}'
+        expected_str = f'{pool.BaseTaskPool.__name__}-{self.TEST_POOL_NAME}'
         self.assertEqual(expected_str, str(self.task_pool))
-        setattr(self.task_pool, '_name', None)
+        self.task_pool._name = None
         expected_str = f'{pool.BaseTaskPool.__name__}-{self.task_pool._idx}'
         self.assertEqual(expected_str, str(self.task_pool))
 
     def test_pool_size(self):
         self.pool_size_patcher.stop()
-        self.task_pool._pool_size = self.test_pool_size
+        self.task_pool._pool_size = self.TEST_POOL_SIZE
-        self.assertEqual(self.test_pool_size, self.task_pool.pool_size)
+        self.assertEqual(self.TEST_POOL_SIZE, self.task_pool.pool_size)
 
         with self.assertRaises(ValueError):
             self.task_pool.pool_size = -1
@@ -93,9 +124,23 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.task_pool.pool_size = new_size = 69
         self.assertEqual(new_size, self.task_pool._pool_size)
 
-    def test_is_open(self):
+    def test_is_locked(self):
-        self.task_pool._open = FOO
+        self.task_pool._locked = FOO
-        self.assertEqual(FOO, self.task_pool.is_open)
+        self.assertEqual(FOO, self.task_pool.is_locked)
+
+    def test_lock(self):
+        assert not self.task_pool._locked
+        self.task_pool.lock()
+        self.assertTrue(self.task_pool._locked)
+        self.task_pool.lock()
+        self.assertTrue(self.task_pool._locked)
+
+    def test_unlock(self):
+        self.task_pool._locked = True
+        self.task_pool.unlock()
+        self.assertFalse(self.task_pool._locked)
+        self.task_pool.unlock()
+        self.assertFalse(self.task_pool._locked)
 
     def test_num_running(self):
         self.task_pool._running = ['foo', 'bar', 'baz']
@@ -201,11 +246,9 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
     @patch.object(pool, 'create_task')
     @patch.object(pool.BaseTaskPool, '_task_wrapper', new_callable=MagicMock)
     @patch.object(pool.BaseTaskPool, '_task_name', return_value=FOO)
-    @patch.object(pool.BaseTaskPool, 'is_open', new_callable=PropertyMock)
+    async def test__start_task(self, mock__task_name: MagicMock, mock__task_wrapper: AsyncMock,
-    async def test__start_task(self, mock_is_open: MagicMock, mock__task_name: MagicMock,
+                               mock_create_task: MagicMock):
-                               mock__task_wrapper: AsyncMock, mock_create_task: MagicMock):
         def reset_mocks() -> None:
-            mock_is_open.reset_mock()
             mock__task_name.reset_mock()
             mock__task_wrapper.reset_mock()
             mock_create_task.reset_mock()
@@ -216,31 +259,27 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.task_pool._counter = count = 123
         self.task_pool._enough_room._value = room = 123
 
+        def check_nothing_changed() -> None:
+            self.assertEqual(count, self.task_pool._counter)
+            self.assertNotIn(count, self.task_pool._running)
+            self.assertEqual(room, self.task_pool._enough_room._value)
+            mock__task_name.assert_not_called()
+            mock__task_wrapper.assert_not_called()
+            mock_create_task.assert_not_called()
+            reset_mocks()
+
         with self.assertRaises(exceptions.NotCoroutine):
             await self.task_pool._start_task(MagicMock(), end_callback=mock_end_cb, cancel_callback=mock_cancel_cb)
-        self.assertEqual(count, self.task_pool._counter)
+        check_nothing_changed()
-        self.assertNotIn(count, self.task_pool._running)
-        self.assertEqual(room, self.task_pool._enough_room._value)
-        mock_is_open.assert_not_called()
-        mock__task_name.assert_not_called()
-        mock__task_wrapper.assert_not_called()
-        mock_create_task.assert_not_called()
-        reset_mocks()
 
-        mock_is_open.return_value = ignore_closed = False
+        self.task_pool._locked = True
+        ignore_closed = False
         mock_awaitable = mock_coroutine()
-        with self.assertRaises(exceptions.PoolIsClosed):
+        with self.assertRaises(exceptions.PoolIsLocked):
             await self.task_pool._start_task(mock_awaitable, ignore_closed,
                                              end_callback=mock_end_cb, cancel_callback=mock_cancel_cb)
         await mock_awaitable
-        self.assertEqual(count, self.task_pool._counter)
+        check_nothing_changed()
-        self.assertNotIn(count, self.task_pool._running)
-        self.assertEqual(room, self.task_pool._enough_room._value)
-        mock_is_open.assert_called_once_with()
-        mock__task_name.assert_not_called()
-        mock__task_wrapper.assert_not_called()
-        mock_create_task.assert_not_called()
-        reset_mocks()
 
         ignore_closed = True
         mock_awaitable = mock_coroutine()
@@ -251,7 +290,6 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.assertEqual(count + 1, self.task_pool._counter)
         self.assertEqual(mock_task, self.task_pool._running[count])
         self.assertEqual(room - 1, self.task_pool._enough_room._value)
-        mock_is_open.assert_called_once_with()
         mock__task_name.assert_called_once_with(count)
         mock__task_wrapper.assert_called_once_with(mock_awaitable, count, mock_end_cb, mock_cancel_cb)
         mock_create_task.assert_called_once_with(mock_wrapped, name=FOO)
@@ -270,7 +308,6 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.assertEqual(count + 1, self.task_pool._counter)
         self.assertNotIn(count, self.task_pool._running)
         self.assertEqual(room, self.task_pool._enough_room._value)
-        mock_is_open.assert_called_once_with()
         mock__task_name.assert_called_once_with(count)
         mock__task_wrapper.assert_called_once_with(mock_awaitable, count, mock_end_cb, mock_cancel_cb)
         mock_create_task.assert_called_once_with(mock_wrapped, name=FOO)
@@ -335,11 +372,6 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.assertDictEqual(self.task_pool._ended, EMPTY_DICT)
         self.assertDictEqual(self.task_pool._cancelled, EMPTY_DICT)
 
-    def test_close(self):
-        assert self.task_pool._open
-        self.task_pool.close()
-        self.assertFalse(self.task_pool._open)
-
     async def test_gather(self):
         test_exception = TestException()
         mock_ended_func, mock_cancelled_func = AsyncMock(return_value=FOO), AsyncMock(side_effect=test_exception)
@@ -351,8 +383,8 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.task_pool._running = running = {789: mock_running_func()}
         self.task_pool._interrupt_flag.set()
 
-        assert self.task_pool._open
+        assert not self.task_pool._locked
-        with self.assertRaises(exceptions.PoolStillOpen):
+        with self.assertRaises(exceptions.PoolStillUnlocked):
             await self.task_pool.gather()
         self.assertDictEqual(self.task_pool._ended, ended)
         self.assertDictEqual(self.task_pool._cancelled, cancelled)
@@ -360,7 +392,7 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.assertListEqual(self.task_pool._before_gathering, before_gather)
         self.assertTrue(self.task_pool._interrupt_flag.is_set())
 
-        self.task_pool._open = False
+        self.task_pool._locked = True
 
         def check_assertions(output) -> None:
             self.assertListEqual([FOO, test_exception, BAR], output)
@@ -377,3 +409,283 @@ class BaseTaskPoolTestCase(IsolatedAsyncioTestCase):
         self.task_pool._cancelled = {456: mock_cancelled_func()}
         self.task_pool._running = {789: mock_running_func()}
         check_assertions(await self.task_pool.gather(return_exceptions=True))
+
+
+class TaskPoolTestCase(CommonTestCase):
+    TEST_CLASS = pool.TaskPool
+    task_pool: pool.TaskPool
+
+    @patch.object(pool.TaskPool, '_start_task')
+    async def test__apply_one(self, mock__start_task: AsyncMock):
+        mock__start_task.return_value = expected_output = 12345
+        mock_awaitable = MagicMock()
+        mock_func = MagicMock(return_value=mock_awaitable)
+        args, kwargs = (FOO, BAR), {'a': 1, 'b': 2}
+        end_cb, cancel_cb = MagicMock(), MagicMock()
+        output = await self.task_pool._apply_one(mock_func, args, kwargs, end_cb, cancel_cb)
+        self.assertEqual(expected_output, output)
+        mock_func.assert_called_once_with(*args, **kwargs)
+        mock__start_task.assert_awaited_once_with(mock_awaitable, end_callback=end_cb, cancel_callback=cancel_cb)
+
+        mock_func.reset_mock()
+        mock__start_task.reset_mock()
+
+        output = await self.task_pool._apply_one(mock_func, args, None, end_cb, cancel_cb)
+        self.assertEqual(expected_output, output)
+        mock_func.assert_called_once_with(*args)
+        mock__start_task.assert_awaited_once_with(mock_awaitable, end_callback=end_cb, cancel_callback=cancel_cb)
+
+    @patch.object(pool.TaskPool, '_apply_one')
+    async def test_apply(self, mock__apply_one: AsyncMock):
+        mock__apply_one.return_value = mock_id = 67890
+        mock_func, num = MagicMock(), 3
+        args, kwargs = (FOO, BAR), {'a': 1, 'b': 2}
+        end_cb, cancel_cb = MagicMock(), MagicMock()
+        expected_output = num * [mock_id]
+        output = await self.task_pool.apply(mock_func, args, kwargs, num, end_cb, cancel_cb)
+        self.assertEqual(expected_output, output)
+        mock__apply_one.assert_has_awaits(num * [call(mock_func, args, kwargs, end_cb, cancel_cb)])
+
+    async def test__queue_producer(self):
+        mock_put = AsyncMock()
+        mock_q = MagicMock(put=mock_put)
+        args = (FOO, BAR, 123)
+        assert not self.task_pool._interrupt_flag.is_set()
+        self.assertIsNone(await self.task_pool._queue_producer(mock_q, args))
+        mock_put.assert_has_awaits([call(arg) for arg in args])
+        mock_put.reset_mock()
+        self.task_pool._interrupt_flag.set()
+        self.assertIsNone(await self.task_pool._queue_producer(mock_q, args))
+        mock_put.assert_not_awaited()
+
+    @patch.object(pool, 'partial')
+    @patch.object(pool, 'star_function')
+    @patch.object(pool.TaskPool, '_start_task')
+    async def test__queue_consumer(self, mock__start_task: AsyncMock, mock_star_function: MagicMock,
+                                   mock_partial: MagicMock):
+        mock_partial.return_value = queue_callback = 'not really'
+        mock_star_function.return_value = awaitable = 'totally an awaitable'
+        q, arg = Queue(), 420.69
+        q.put_nowait(arg)
+        mock_func, stars = MagicMock(), 3
+        mock_flag, end_cb, cancel_cb = MagicMock(), MagicMock(), MagicMock()
+        self.assertIsNone(await self.task_pool._queue_consumer(q, mock_flag, mock_func, stars, end_cb, cancel_cb))
+        self.assertTrue(q.empty())
+        mock__start_task.assert_awaited_once_with(awaitable, ignore_lock=True,
+                                                  end_callback=queue_callback, cancel_callback=cancel_cb)
+        mock_star_function.assert_called_once_with(mock_func, arg, arg_stars=stars)
+        mock_partial.assert_called_once_with(pool.TaskPool._queue_callback, self.task_pool,
+                                             q=q, first_batch_started=mock_flag, func=mock_func, arg_stars=stars,
+                                             end_callback=end_cb, cancel_callback=cancel_cb)
+        mock__start_task.reset_mock()
+        mock_star_function.reset_mock()
+        mock_partial.reset_mock()
+
+        self.assertIsNone(await self.task_pool._queue_consumer(q, mock_flag, mock_func, stars, end_cb, cancel_cb))
+        self.assertTrue(q.empty())
+        mock__start_task.assert_not_awaited()
+        mock_star_function.assert_not_called()
+        mock_partial.assert_not_called()
+
+    @patch.object(pool, 'execute_optional')
+    @patch.object(pool.TaskPool, '_queue_consumer')
+    async def test__queue_callback(self, mock__queue_consumer: AsyncMock, mock_execute_optional: AsyncMock):
+        task_id, mock_q = 420, MagicMock()
+        mock_func, stars = MagicMock(), 3
+        mock_wait = AsyncMock()
+        mock_flag = MagicMock(wait=mock_wait)
+        end_cb, cancel_cb = MagicMock(), MagicMock()
+        self.assertIsNone(await self.task_pool._queue_callback(task_id, mock_q, mock_flag, mock_func, stars,
+                                                               end_callback=end_cb, cancel_callback=cancel_cb))
+        mock_wait.assert_awaited_once_with()
+        mock__queue_consumer.assert_awaited_once_with(mock_q, mock_flag, mock_func, stars,
+                                                      end_callback=end_cb, cancel_callback=cancel_cb)
+        mock_execute_optional.assert_awaited_once_with(end_cb, args=(task_id,))
+
+    @patch.object(pool, 'iter')
+    @patch.object(pool, 'create_task')
+    @patch.object(pool, 'join_queue', new_callable=MagicMock)
+    @patch.object(pool.TaskPool, '_queue_producer', new_callable=MagicMock)
+    async def test__set_up_args_queue(self, mock__queue_producer: MagicMock, mock_join_queue: MagicMock,
+                                      mock_create_task: MagicMock, mock_iter: MagicMock):
+        args, num_tasks = (FOO, BAR, 1, 2, 3), 2
+        mock_join_queue.return_value = mock_join = 'awaitable'
+        mock_iter.return_value = args_iter = iter(args)
+        mock__queue_producer.return_value = mock_producer_coro = 'very awaitable'
+        output_q = self.task_pool._set_up_args_queue(args, num_tasks)
+        self.assertIsInstance(output_q, Queue)
+        self.assertEqual(num_tasks, output_q.qsize())
+        for arg in args[:num_tasks]:
+            self.assertEqual(arg, output_q.get_nowait())
+        self.assertTrue(output_q.empty())
+        for arg in args[num_tasks:]:
+            self.assertEqual(arg, next(args_iter))
+        with self.assertRaises(StopIteration):
+            next(args_iter)
+        self.assertListEqual([mock_join], self.task_pool._before_gathering)
+        mock_join_queue.assert_called_once_with(output_q)
+        mock__queue_producer.assert_called_once_with(output_q, args_iter)
+        mock_create_task.assert_called_once_with(mock_producer_coro)
+
+        self.task_pool._before_gathering.clear()
+        mock_join_queue.reset_mock()
+        mock__queue_producer.reset_mock()
+        mock_create_task.reset_mock()
+
+        num_tasks = 6
+        mock_iter.return_value = args_iter = iter(args)
+        output_q = self.task_pool._set_up_args_queue(args, num_tasks)
+        self.assertIsInstance(output_q, Queue)
+        self.assertEqual(len(args), output_q.qsize())
+        for arg in args:
+            self.assertEqual(arg, output_q.get_nowait())
+        self.assertTrue(output_q.empty())
+        with self.assertRaises(StopIteration):
+            next(args_iter)
+        self.assertListEqual([mock_join], self.task_pool._before_gathering)
+        mock_join_queue.assert_called_once_with(output_q)
+        mock__queue_producer.assert_not_called()
+        mock_create_task.assert_not_called()
+
+    @patch.object(pool, 'Event')
+    @patch.object(pool.TaskPool, '_queue_consumer')
+    @patch.object(pool.TaskPool, '_set_up_args_queue')
+    async def test__map(self, mock__set_up_args_queue: MagicMock, mock__queue_consumer: AsyncMock,
+                        mock_event_cls: MagicMock):
+        qsize = 4
+        mock__set_up_args_queue.return_value = mock_q = MagicMock(qsize=MagicMock(return_value=qsize))
+        mock_flag_set = MagicMock()
+        mock_event_cls.return_value = mock_flag = MagicMock(set=mock_flag_set)
+
+        mock_func, stars = MagicMock(), 3
+        args_iter, num_tasks = (FOO, BAR, 1, 2, 3), 2
+        end_cb, cancel_cb = MagicMock(), MagicMock()
+
+        self.task_pool._locked = False
+        with self.assertRaises(exceptions.PoolIsLocked):
+            await self.task_pool._map(mock_func, args_iter, stars, num_tasks, end_cb, cancel_cb)
+        mock__set_up_args_queue.assert_not_called()
+        mock__queue_consumer.assert_not_awaited()
+        mock_flag_set.assert_not_called()
+
+        self.task_pool._locked = True
+        self.assertIsNone(await self.task_pool._map(mock_func, args_iter, stars, num_tasks, end_cb, cancel_cb))
+        mock__set_up_args_queue.assert_called_once_with(args_iter, num_tasks)
+        mock__queue_consumer.assert_has_awaits(qsize * [call(mock_q, mock_flag, mock_func, arg_stars=stars,
+                                                             end_callback=end_cb, cancel_callback=cancel_cb)])
+        mock_flag_set.assert_called_once_with()
+
+    @patch.object(pool.TaskPool, '_map')
+    async def test_map(self, mock__map: AsyncMock):
+        mock_func = MagicMock()
+        arg_iter, num_tasks = (FOO, BAR, 1, 2, 3), 2
+        end_cb, cancel_cb = MagicMock(), MagicMock()
+        self.assertIsNone(await self.task_pool.map(mock_func, arg_iter, num_tasks, end_cb, cancel_cb))
+        mock__map.assert_awaited_once_with(mock_func, arg_iter, arg_stars=0, num_tasks=num_tasks,
+                                           end_callback=end_cb, cancel_callback=cancel_cb)
+
+    @patch.object(pool.TaskPool, '_map')
+    async def test_starmap(self, mock__map: AsyncMock):
+        mock_func = MagicMock()
+        args_iter, num_tasks = ([FOO], [BAR]), 2
+        end_cb, cancel_cb = MagicMock(), MagicMock()
+        self.assertIsNone(await self.task_pool.starmap(mock_func, args_iter, num_tasks, end_cb, cancel_cb))
+        mock__map.assert_awaited_once_with(mock_func, args_iter, arg_stars=1, num_tasks=num_tasks,
+                                           end_callback=end_cb, cancel_callback=cancel_cb)
+
+    @patch.object(pool.TaskPool, '_map')
+    async def test_doublestarmap(self, mock__map: AsyncMock):
+        mock_func = MagicMock()
+        kwargs_iter, num_tasks = [{'a': FOO}, {'a': BAR}], 2
+        end_cb, cancel_cb = MagicMock(), MagicMock()
+        self.assertIsNone(await self.task_pool.doublestarmap(mock_func, kwargs_iter, num_tasks, end_cb, cancel_cb))
+        mock__map.assert_awaited_once_with(mock_func, kwargs_iter, arg_stars=2, num_tasks=num_tasks,
+                                           end_callback=end_cb, cancel_callback=cancel_cb)
+
+
+class SimpleTaskPoolTestCase(CommonTestCase):
+    TEST_CLASS = pool.SimpleTaskPool
+    task_pool: pool.SimpleTaskPool
+
+    TEST_POOL_FUNC = AsyncMock(__name__=FOO)
+    TEST_POOL_ARGS = (FOO, BAR)
+    TEST_POOL_KWARGS = {'a': 1, 'b': 2}
+    TEST_POOL_END_CB = MagicMock()
+    TEST_POOL_CANCEL_CB = MagicMock()
+
+    def get_task_pool_init_params(self) -> dict:
+        return super().get_task_pool_init_params() | {
+            'func': self.TEST_POOL_FUNC,
+            'args': self.TEST_POOL_ARGS,
+            'kwargs': self.TEST_POOL_KWARGS,
+            'end_callback': self.TEST_POOL_END_CB,
+            'cancel_callback': self.TEST_POOL_CANCEL_CB,
+        }
+
+    def setUp(self) -> None:
+        self.base_class_init_patcher = patch.object(pool.BaseTaskPool, '__init__')
+        self.base_class_init = self.base_class_init_patcher.start()
+        super().setUp()
+
+    def tearDown(self) -> None:
+        self.base_class_init_patcher.stop()
+
+    def test_init(self):
+        self.assertEqual(self.TEST_POOL_FUNC, self.task_pool._func)
+        self.assertEqual(self.TEST_POOL_ARGS, self.task_pool._args)
+        self.assertEqual(self.TEST_POOL_KWARGS, self.task_pool._kwargs)
+        self.assertEqual(self.TEST_POOL_END_CB, self.task_pool._end_callback)
+        self.assertEqual(self.TEST_POOL_CANCEL_CB, self.task_pool._cancel_callback)
+        self.base_class_init.assert_called_once_with(pool_size=self.TEST_POOL_SIZE, name=self.TEST_POOL_NAME)
+
+        with self.assertRaises(exceptions.NotCoroutine):
+            pool.SimpleTaskPool(MagicMock())
+
+    def test_func_name(self):
+        self.assertEqual(self.TEST_POOL_FUNC.__name__, self.task_pool.func_name)
+
+    @patch.object(pool.SimpleTaskPool, '_start_task')
+    async def test__start_one(self, mock__start_task: AsyncMock):
+        mock__start_task.return_value = expected_output = 99
+        self.task_pool._func = MagicMock(return_value=BAR)
+        output = await self.task_pool._start_one()
+        self.assertEqual(expected_output, output)
+        self.task_pool._func.assert_called_once_with(*self.task_pool._args, **self.task_pool._kwargs)
+        mock__start_task.assert_awaited_once_with(BAR, end_callback=self.task_pool._end_callback,
+                                                  cancel_callback=self.task_pool._cancel_callback)
+
+    @patch.object(pool.SimpleTaskPool, '_start_one')
+    async def test_start(self, mock__start_one: AsyncMock):
+        mock__start_one.return_value = FOO
+        num = 5
+        output = await self.task_pool.start(num)
+        expected_output = num * [FOO]
+        self.assertListEqual(expected_output, output)
+        mock__start_one.assert_has_awaits(num * [call()])
+
+    @patch.object(pool.SimpleTaskPool, 'cancel')
+    def test_stop(self, mock_cancel: MagicMock):
+        num = 2
+        id1, id2, id3 = 5, 6, 7
+        self.task_pool._running = {id1: FOO, id2: BAR, id3: FOO + BAR}
+        output = self.task_pool.stop(num)
+        expected_output = [id3, id2]
+        self.assertEqual(expected_output, output)
+        mock_cancel.assert_called_once_with(*expected_output)
+        mock_cancel.reset_mock()
+
+        num = 50
+        output = self.task_pool.stop(num)
+        expected_output = [id3, id2, id1]
+        self.assertEqual(expected_output, output)
+        mock_cancel.assert_called_once_with(*expected_output)
+
+    @patch.object(pool.SimpleTaskPool, 'num_running', new_callable=PropertyMock)
+    @patch.object(pool.SimpleTaskPool, 'stop')
+    def test_stop_all(self, mock_stop: MagicMock, mock_num_running: MagicMock):
+        mock_num_running.return_value = num = 9876
+        mock_stop.return_value = expected_output = 'something'
+        output = self.task_pool.stop_all()
+        self.assertEqual(expected_output, output)
+        mock_num_running.assert_called_once_with()
+        mock_stop.assert_called_once_with(num)

usage/USAGE.md

@@ -2,17 +2,17 @@
 
 ## Minimal example for `SimpleTaskPool`
 
-The minimum required setup is a "worker" coroutine function that can do something asynchronously, a main coroutine function that sets up the `SimpleTaskPool` and starts/stops the tasks as desired, eventually awaiting them all. 
+The minimum required setup is a "worker" coroutine function that can do something asynchronously, and a main coroutine function that sets up the `SimpleTaskPool`, starts/stops the tasks as desired, and eventually awaits them all. 
 
 The following demo code enables full log output first for additional clarity. It is complete and should work as is.
 
 ### Code
+
 ```python
 import logging
 import asyncio
 
-from asyncio_taskpool.pool import SimpleTaskPool
+from asyncio_taskpool import SimpleTaskPool
-
 
 logging.getLogger().setLevel(logging.NOTSET)
 logging.getLogger('asyncio_taskpool').addHandler(logging.StreamHandler())
@@ -23,8 +23,8 @@ async def work(n: int) -> None:
     Pseudo-worker function. 
     Counts up to an integer with a second of sleep before each iteration.
     In a real-world use case, a worker function should probably have access 
-    to some synchronisation primitive or shared resource to distribute work 
+    to some synchronisation primitive (such as a queue) or shared resource
-    between an arbitrary number of workers.
+    to distribute work between an arbitrary number of workers.
     """
     for i in range(n):
         await asyncio.sleep(1)
@@ -38,7 +38,7 @@ async def main() -> None:
     await pool.start()  # launches work task 3
     await asyncio.sleep(1.5)  # lets the tasks work for a bit
     pool.stop(2)  # cancels tasks 3 and 2
-    pool.close()  # required for the last line
+    pool.lock()  # required for the last line
     await pool.gather()  # awaits all tasks, then flushes the pool
 
 
@@ -60,7 +60,7 @@ did 1
 did 1
 did 1
 did 0
-SimpleTaskPool-0 is closed!
+SimpleTaskPool-0 is locked!
 Cancelling SimpleTaskPool-0_Task-3 ...
 Cancelled SimpleTaskPool-0_Task-3
 Ended SimpleTaskPool-0_Task-3
@@ -77,6 +77,157 @@ did 4
 did 4
 ```
 
-## Advanced example
+## Advanced example for `TaskPool`
 
-...
+This time, we want to start tasks from _different_ coroutine functions **and** with _different_ arguments. For this we need an instance of the more generalized `TaskPool` class.
+
+As with the simple example, we need "worker" coroutine functions that can do something asynchronously, as well as a main coroutine function that sets up the pool, starts the tasks, and eventually awaits them.
+
+The following demo code enables full log output first for additional clarity. It is complete and should work as is.
+
+### Code
+
+```python
+import logging
+import asyncio
+
+from asyncio_taskpool import TaskPool
+
+logging.getLogger().setLevel(logging.NOTSET)
+logging.getLogger('asyncio_taskpool').addHandler(logging.StreamHandler())
+
+
+async def work(start: int, stop: int, step: int = 1) -> None:
+    """Pseudo-worker function counting through a range with a second of sleep in between each iteration."""
+    for i in range(start, stop, step):
+        await asyncio.sleep(1)
+        print("work with", i)
+
+
+async def other_work(a: int, b: int) -> None:
+    """Different pseudo-worker counting through a range with half a second of sleep in between each iteration."""
+    for i in range(a, b):
+        await asyncio.sleep(0.5)
+        print("other_work with", i)
+
+
+async def main() -> None:
+    # Initialize a new task pool instance and limit its size to 3 tasks.
+    pool = TaskPool(3)
+    # Queue up two tasks (IDs 0 and 1) to run concurrently (with the same positional arguments).
+    print("Called `apply`")
+    await pool.apply(work, kwargs={'start': 100, 'stop': 200, 'step': 10}, num=2)
+    # Let the tasks work for a bit.
+    await asyncio.sleep(1.5)
+    # Now, let us enqueue four more tasks (which will receive IDs 2, 3, 4, and 5), each created with different 
+    # positional arguments by using `starmap`, but have **no more than two of those** run concurrently.
+    # Since we set our pool size to 3, and already have two tasks working within the pool,
+    # only the first one of these will start immediately (and receive ID 2).
+    # The second one will start (with ID 3), only once there is room in the pool,
+    # which -- in this example -- will be the case after ID 2 ends;
+    # until then the `starmap` method call **will block**!
+    # Once there is room in the pool again, the third and fourth will each start (with IDs 4 and 5)
+    # **only** once there is room in the pool **and** no more than one of these last four tasks is running.
+    args_list = [(0, 10), (10, 20), (20, 30), (30, 40)]
+    print("Calling `starmap`...")
+    await pool.starmap(other_work, args_list, num_tasks=2)
+    print("`starmap` returned")
+    # Now we lock the pool, so that we can safely await all our tasks.
+    pool.lock()
+    # Finally, we block, until all tasks have ended.
+    print("Called `gather`")
+    await pool.gather()
+    print("Done.")
+
+
+if __name__ == '__main__':
+    asyncio.run(main())
+```
+
+### Output 
+Additional comments for the output are provided with `<---` next to the output lines.
+
+(Keep in mind that the logger and `print` asynchronously write to `stdout`.)
+```
+TaskPool-0 initialized
+Started TaskPool-0_Task-0
+Started TaskPool-0_Task-1
+Called `apply`
+work with 100
+work with 100
+Calling `starmap`...    <--- notice that this blocks as expected
+Started TaskPool-0_Task-2
+work with 110
+work with 110
+other_work with 0
+other_work with 1
+work with 120
+work with 120
+other_work with 2
+other_work with 3
+work with 130
+work with 130
+other_work with 4
+other_work with 5
+work with 140
+work with 140
+other_work with 6
+other_work with 7
+work with 150
+work with 150
+other_work with 8
+Ended TaskPool-0_Task-2    <--- here Task-2 makes room in the pool and unblocks `main()`
+TaskPool-0 is locked!
+Started TaskPool-0_Task-3
+other_work with 9
+`starmap` returned
+Called `gather`    <--- now this will block `main()` until all tasks have ended
+work with 160
+work with 160
+other_work with 10
+other_work with 11
+work with 170
+work with 170
+other_work with 12
+other_work with 13
+work with 180
+work with 180
+other_work with 14
+other_work with 15
+Ended TaskPool-0_Task-0
+Ended TaskPool-0_Task-1    <--- even though there is room in the pool now, Task-5 will not start
+Started TaskPool-0_Task-4
+work with 190
+work with 190
+other_work with 16
+other_work with 20
+other_work with 17
+other_work with 21
+other_work with 18
+other_work with 22
+other_work with 19
+Ended TaskPool-0_Task-3    <--- now that only Task-4 is left, Task-5 will start
+Started TaskPool-0_Task-5
+other_work with 23
+other_work with 30
+other_work with 24
+other_work with 31
+other_work with 25
+other_work with 32
+other_work with 26
+other_work with 33
+other_work with 27
+other_work with 34
+other_work with 28
+other_work with 35
+Ended TaskPool-0_Task-4
+other_work with 29
+other_work with 36
+other_work with 37
+other_work with 38
+other_work with 39
+Done.
+Ended TaskPool-0_Task-5
+```
+
+© 2022 Daniil Fajnberg

usage/example_server.py

@@ -1,3 +1,25 @@
+__author__ = "Daniil Fajnberg"
+__copyright__ = "Copyright © 2022 Daniil Fajnberg"
+__license__ = """GNU LGPLv3.0
+
+This file is part of asyncio-taskpool.
+
+asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
+version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
+
+asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
+If not, see <https://www.gnu.org/licenses/>."""
+
+__doc__ = """
+Working example of a UnixControlServer in combination with the SimpleTaskPool.
+Use the main CLI client to interface at the socket.
+"""
+
+
 import asyncio
 import logging
 
@@ -48,12 +70,12 @@ async def main() -> None:
     control_server_task = await UnixControlServer(pool, path='/tmp/py_asyncio_taskpool.sock').serve_forever()
     # We block until `.task_done()` has been called once by our workers for every item placed into the queue.
     await q.join()
-    # Since we don't need any "work" done anymore, we can close our control server by cancelling the task.
+    # Since we don't need any "work" done anymore, we can lock our control server by cancelling the task.
     control_server_task.cancel()
     # Since our workers should now be stuck waiting for more items to pick from the queue, but no items are left,
     # we can now safely cancel their tasks.
     pool.stop_all()
-    pool.close()
+    pool.lock()
     # Finally we allow for all tasks to do do their cleanup, if they need to do any, upon being cancelled.
     # We block until they all return or raise an exception, but since we are not interested in any of their exceptions,
     # we just silently collect their exceptions along with their return values.