added tests for 'chat.py'

chatmastermind/chat.py

@@ -0,0 +1,269 @@
+"""
+Module implementing various chat classes and functions for managing a chat history.
+"""
+import shutil
+import pathlib
+from pprint import PrettyPrinter
+from pydoc import pager
+from dataclasses import dataclass
+from typing import TypeVar, Type, Optional, ClassVar, Any, Callable
+from .message import Question, Answer, Message, MessageFilter, MessageError, source_code, message_in
+from .tags import Tag
+
+ChatInst = TypeVar('ChatInst', bound='Chat')
+ChatDBInst = TypeVar('ChatDBInst', bound='ChatDB')
+
+
+class ChatError(Exception):
+    pass
+
+
+def terminal_width() -> int:
+    return shutil.get_terminal_size().columns
+
+
+def pp(*args: Any, **kwargs: Any) -> None:
+    return PrettyPrinter(width=terminal_width()).pprint(*args, **kwargs)
+
+
+def print_paged(text: str) -> None:
+    pager(text)
+
+
+def read_dir(dir_path: pathlib.Path,
+             glob: Optional[str] = None,
+             mfilter: Optional[MessageFilter] = None) -> list[Message]:
+    """
+    Reads the messages from the given folder.
+    Parameters:
+    * 'dir_path': source directory
+    * 'glob': if specified, files will be filtered using 'path.glob()',
+      otherwise it uses 'path.iterdir()'.
+    * 'mfilter': use with 'Message.from_file()' to filter messages
+      when reading them.
+    """
+    messages: list[Message] = []
+    file_iter = dir_path.glob(glob) if glob else dir_path.iterdir()
+    for file_path in sorted(file_iter):
+        if file_path.is_file():
+            try:
+                message = Message.from_file(file_path, mfilter)
+                if message:
+                    messages.append(message)
+            except MessageError as e:
+                print(f"Error processing message in '{file_path}': {str(e)}")
+    return messages
+
+
+def write_dir(dir_path: pathlib.Path,
+              messages: list[Message],
+              file_suffix: str,
+              next_fid: Callable[[], int]) -> None:
+    """
+    Write all messages to the given directory. If a message has no file_path,
+    a new one will be created. If message.file_path exists, it will be modified
+    to point to the given directory.
+    Parameters:
+    * 'dir_path': destination directory
+    * 'messages': list of messages to write
+    * 'file_suffix': suffix for the message files ['.txt'|'.yaml']
+    * 'next_fid': callable that returns the next file ID
+    """
+    for message in messages:
+        file_path = message.file_path
+        # message has no file_path: create one
+        if not file_path:
+            fid = next_fid()
+            fname = f"{fid:04d}{file_suffix}"
+            file_path = dir_path / fname
+        # file_path does not point to given directory: modify it
+        elif not file_path.parent.samefile(dir_path):
+            file_path = dir_path / file_path.name
+        message.to_file(file_path)
+
+
+@dataclass
+class Chat:
+    """
+    A class containing a complete chat history.
+    """
+
+    messages: list[Message]
+
+    def filter(self, mfilter: MessageFilter) -> None:
+        """
+        Use 'Message.match(mfilter) to remove all messages that
+        don't fulfill the filter requirements.
+        """
+        self.messages = [m for m in self.messages if m.match(mfilter)]
+
+    def sort(self, reverse: bool = False) -> None:
+        """
+        Sort the messages according to 'Message.msg_id()'.
+        """
+        try:
+            # the message may not have an ID if it doesn't have a file_path
+            self.messages.sort(key=lambda m: m.msg_id(), reverse=reverse)
+        except MessageError:
+            pass
+
+    def clear(self) -> None:
+        """
+        Delete all messages.
+        """
+        self.messages = []
+
+    def add_msgs(self, msgs: list[Message]) -> None:
+        """
+        Add new messages and sort them if possible.
+        """
+        self.messages += msgs
+        self.sort()
+
+    def tags(self, prefix: Optional[str] = None, contain: Optional[str] = None) -> set[Tag]:
+        """
+        Get the tags of all messages, optionally filtered by prefix or substring.
+        """
+        tags: set[Tag] = set()
+        for m in self.messages:
+            tags |= m.filter_tags(prefix, contain)
+        return tags
+
+    def print(self, dump: bool = False, source_code_only: bool = False,
+              with_tags: bool = False, with_file: bool = False,
+              paged: bool = True) -> None:
+        if dump:
+            pp(self)
+            return
+        output: list[str] = []
+        for message in self.messages:
+            if source_code_only:
+                output.extend(source_code(message.question, include_delims=True))
+                continue
+            output.append('-' * terminal_width())
+            output.append(Question.txt_header)
+            output.append(message.question)
+            if message.answer:
+                output.append(Answer.txt_header)
+                output.append(message.answer)
+            if with_tags:
+                output.append(message.tags_str())
+            if with_file:
+                output.append('FILE: ' + str(message.file_path))
+        if paged:
+            print_paged('\n'.join(output))
+        else:
+            print(*output, sep='\n')
+
+
+@dataclass
+class ChatDB(Chat):
+    """
+    A 'Chat' class that is bound to a given directory structure. Supports reading
+    and writing messages from / to that structure. Such a structure consists of
+    two directories: a 'cache directory', where all messages are temporarily
+    stored, and a 'DB' directory, where selected messages can be stored
+    persistently.
+    """
+
+    default_file_suffix: ClassVar[str] = '.txt'
+
+    cache_path: pathlib.Path
+    db_path: pathlib.Path
+    # a MessageFilter that all messages must match (if given)
+    mfilter: Optional[MessageFilter] = None
+    file_suffix: str = default_file_suffix
+    # the glob pattern for all messages
+    glob: Optional[str] = None
+
+    def __post_init__(self) -> None:
+        # contains the latest message ID
+        self.next_fname = self.db_path / '.next'
+
+    @classmethod
+    def from_dir(cls: Type[ChatDBInst],
+                 cache_path: pathlib.Path,
+                 db_path: pathlib.Path,
+                 glob: Optional[str] = None,
+                 mfilter: Optional[MessageFilter] = None) -> ChatDBInst:
+        """
+        Create a 'ChatDB' instance from the given directory structure.
+        Reads all messages from 'db_path' into the local message list.
+        Parameters:
+        * 'cache_path': path to the directory for temporary messages
+        * 'db_path': path to the directory for persistent messages
+        * 'glob': if specified, files will be filtered using 'path.glob()',
+          otherwise it uses 'path.iterdir()'.
+        * 'mfilter': use with 'Message.from_file()' to filter messages
+          when reading them.
+        """
+        messages = read_dir(db_path, glob, mfilter)
+        return cls(messages, cache_path, db_path, mfilter,
+                   cls.default_file_suffix, glob)
+
+    @classmethod
+    def from_messages(cls: Type[ChatDBInst],
+                      cache_path: pathlib.Path,
+                      db_path: pathlib.Path,
+                      messages: list[Message],
+                      mfilter: Optional[MessageFilter] = None) -> ChatDBInst:
+        """
+        Create a ChatDB instance from the given message list.
+        """
+        return cls(messages, cache_path, db_path, mfilter)
+
+    def get_next_fid(self) -> int:
+        try:
+            with open(self.next_fname, 'r') as f:
+                next_fid = int(f.read()) + 1
+            self.set_next_fid(next_fid)
+            return next_fid
+        except Exception:
+            self.set_next_fid(1)
+            return 1
+
+    def set_next_fid(self, fid: int) -> None:
+        with open(self.next_fname, 'w') as f:
+            f.write(f'{fid}')
+
+    def read_db(self) -> None:
+        """
+        Reads new messages from the DB directory. New ones are added to the internal list,
+        existing ones are kept or replaced. A message is determined as 'existing' if a
+        message with the same base filename (i. e. 'file_path.name') is already in the list.
+        """
+        new_messages = read_dir(self.db_path, self.glob, self.mfilter)
+        # remove all messages from self.messages that are in the new list
+        self.messages = [m for m in self.messages if not message_in(m, new_messages)]
+        # copy the messages from the temporary list to self.messages and sort them
+        self.messages += new_messages
+        self.sort()
+
+    def read_cache(self) -> None:
+        """
+        Reads new messages from the cache directory. New ones are added to the internal list,
+        existing ones are kept or replaced. A message is determined as 'existing' if a
+        message with the same base filename (i. e. 'file_path.name') is already in the list.
+        """
+        new_messages = read_dir(self.db_path, self.glob, self.mfilter)
+        # remove all messages from self.messages that are in the new list
+        self.messages = [m for m in self.messages if not message_in(m, new_messages)]
+        # copy the messages from the temporary list to self.messages and sort them
+        self.messages += new_messages
+        self.sort()
+
+    def write_db(self) -> None:
+        """
+        Write all messages to the DB directory. If a message has no file_path,
+        a new one will be created. If message.file_path exists, it will be modified
+        to point to the DB directory.
+        """
+        write_dir(self.db_path, self.messages, self.file_suffix, self.get_next_fid)
+
+    def write_cache(self) -> None:
+        """
+        Write all messages to the cache directory. If a message has no file_path,
+        a new one will be created. If message.file_path exists, it will be modified
+        to point to the cache directory.
+        """
+        write_dir(self.cache_path, self.messages, self.file_suffix, self.get_next_fid)

chatmastermind/message.py

@@ -3,7 +3,7 @@ Module implementing message related functions and classes.
 """
 import pathlib
 import yaml
-from typing import Type, TypeVar, ClassVar, Optional, Any, Union, Final, Literal
+from typing import Type, TypeVar, ClassVar, Optional, Any, Union, Final, Literal, Iterable
 from dataclasses import dataclass, asdict, field
 from .tags import Tag, TagLine, TagError, match_tags
 
@@ -57,6 +57,20 @@ def source_code(text: str, include_delims: bool = False) -> list[str]:
     return code_sections
 
 
+def message_in(message: MessageInst, messages: Iterable[MessageInst]) -> bool:
+    """
+    Searches the given message list for a message with the same file
+    name as the given one (i. e. it compares Message.file_path.name).
+    If the given message has no file_path, False is returned.
+    """
+    if not message.file_path:
+        return False
+    for m in messages:
+        if m.file_path and m.file_path.name == message.file_path.name:
+            return True
+    return False
+
+
 @dataclass(kw_only=True)
 class MessageFilter:
     """
@@ -436,13 +450,14 @@ class Message():
         Filter tags based on their prefix (i. e. the tag starts with a given string)
         or some contained string.
         """
-        res_tags = self.tags
-        if res_tags:
-            if prefix and len(prefix) > 0:
-                res_tags -= {tag for tag in res_tags if not tag.startswith(prefix)}
-            if contain and len(contain) > 0:
-                res_tags -= {tag for tag in res_tags if contain not in tag}
-        return res_tags or set()
+        if not self.tags:
+            return set()
+        res_tags = self.tags.copy()
+        if prefix and len(prefix) > 0:
+            res_tags -= {tag for tag in res_tags if not tag.startswith(prefix)}
+        if contain and len(contain) > 0:
+            res_tags -= {tag for tag in res_tags if contain not in tag}
+        return res_tags
 
     def tags_str(self, prefix: Optional[str] = None, contain: Optional[str] = None) -> str:
         """

tests/test_chat.py

@@ -0,0 +1,234 @@
+import pathlib
+import tempfile
+import time
+from io import StringIO
+from unittest.mock import patch
+from chatmastermind.tags import TagLine
+from chatmastermind.message import Message, Question, Answer, Tag, MessageFilter
+from chatmastermind.chat import Chat, ChatDB, terminal_width
+from .test_main import CmmTestCase
+
+
+class TestChat(CmmTestCase):
+    def setUp(self) -> None:
+        self.chat = Chat([])
+        self.message1 = Message(Question('Question 1'),
+                                Answer('Answer 1'),
+                                {Tag('atag1')},
+                                file_path=pathlib.Path('0001.txt'))
+        self.message2 = Message(Question('Question 2'),
+                                Answer('Answer 2'),
+                                {Tag('btag2')},
+                                file_path=pathlib.Path('0002.txt'))
+
+    def test_filter(self) -> None:
+        self.chat.add_msgs([self.message1, self.message2])
+        self.chat.filter(MessageFilter(answer_contains='Answer 1'))
+
+        self.assertEqual(len(self.chat.messages), 1)
+        self.assertEqual(self.chat.messages[0].question, 'Question 1')
+
+    def test_sort(self) -> None:
+        self.chat.add_msgs([self.message2, self.message1])
+        self.chat.sort()
+        self.assertEqual(self.chat.messages[0].question, 'Question 1')
+        self.assertEqual(self.chat.messages[1].question, 'Question 2')
+        self.chat.sort(reverse=True)
+        self.assertEqual(self.chat.messages[0].question, 'Question 2')
+        self.assertEqual(self.chat.messages[1].question, 'Question 1')
+
+    def test_clear(self) -> None:
+        self.chat.add_msgs([self.message1])
+        self.chat.clear()
+        self.assertEqual(len(self.chat.messages), 0)
+
+    def test_add_msgs(self) -> None:
+        self.chat.add_msgs([self.message1, self.message2])
+        self.assertEqual(len(self.chat.messages), 2)
+        self.assertEqual(self.chat.messages[0].question, 'Question 1')
+        self.assertEqual(self.chat.messages[1].question, 'Question 2')
+
+    def test_tags(self) -> None:
+        self.chat.add_msgs([self.message1, self.message2])
+        tags_all = self.chat.tags()
+        self.assertSetEqual(tags_all, {Tag('atag1'), Tag('btag2')})
+        tags_pref = self.chat.tags(prefix='a')
+        self.assertSetEqual(tags_pref, {Tag('atag1')})
+        tags_cont = self.chat.tags(contain='2')
+        self.assertSetEqual(tags_cont, {Tag('btag2')})
+
+    @patch('sys.stdout', new_callable=StringIO)
+    def test_print(self, mock_stdout: StringIO) -> None:
+        self.chat.add_msgs([self.message1, self.message2])
+        self.chat.print(paged=False)
+        expected_output = f"""{'-'*terminal_width()}
+{Question.txt_header}
+Question 1
+{Answer.txt_header}
+Answer 1
+{'-'*terminal_width()}
+{Question.txt_header}
+Question 2
+{Answer.txt_header}
+Answer 2
+"""
+        self.assertEqual(mock_stdout.getvalue(), expected_output)
+
+    @patch('sys.stdout', new_callable=StringIO)
+    def test_print_with_tags_and_file(self, mock_stdout: StringIO) -> None:
+        self.chat.add_msgs([self.message1, self.message2])
+        self.chat.print(paged=False, with_tags=True, with_file=True)
+        expected_output = f"""{'-'*terminal_width()}
+{Question.txt_header}
+Question 1
+{Answer.txt_header}
+Answer 1
+{TagLine.prefix} atag1
+FILE: 0001.txt
+{'-'*terminal_width()}
+{Question.txt_header}
+Question 2
+{Answer.txt_header}
+Answer 2
+{TagLine.prefix} btag2
+FILE: 0002.txt
+"""
+        self.assertEqual(mock_stdout.getvalue(), expected_output)
+
+
+class TestChatDB(CmmTestCase):
+    def setUp(self) -> None:
+        self.db_path = tempfile.TemporaryDirectory()
+        self.cache_path = tempfile.TemporaryDirectory()
+
+        self.message1 = Message(Question('Question 1'),
+                                Answer('Answer 1'),
+                                {Tag('tag1')},
+                                file_path=pathlib.Path('0001.txt'))
+        self.message2 = Message(Question('Question 2'),
+                                Answer('Answer 2'),
+                                {Tag('tag2')},
+                                file_path=pathlib.Path('0002.yaml'))
+        self.message3 = Message(Question('Question 3'),
+                                Answer('Answer 3'),
+                                {Tag('tag3')},
+                                file_path=pathlib.Path('0003.txt'))
+        self.message4 = Message(Question('Question 4'),
+                                Answer('Answer 4'),
+                                {Tag('tag4')},
+                                file_path=pathlib.Path('0004.yaml'))
+
+        self.message1.to_file(pathlib.Path(self.db_path.name, '0001.txt'))
+        self.message2.to_file(pathlib.Path(self.db_path.name, '0002.yaml'))
+        self.message3.to_file(pathlib.Path(self.db_path.name, '0003.txt'))
+        self.message4.to_file(pathlib.Path(self.db_path.name, '0004.yaml'))
+
+    def tearDown(self) -> None:
+        self.db_path.cleanup()
+        self.cache_path.cleanup()
+        pass
+
+    def test_chat_db_from_dir(self) -> None:
+        chat_db = ChatDB.from_dir(pathlib.Path(self.cache_path.name),
+                                  pathlib.Path(self.db_path.name))
+        self.assertEqual(len(chat_db.messages), 4)
+        self.assertEqual(chat_db.cache_path, pathlib.Path(self.cache_path.name))
+        self.assertEqual(chat_db.db_path, pathlib.Path(self.db_path.name))
+        # check that the files are sorted
+        self.assertEqual(chat_db.messages[0].file_path,
+                         pathlib.Path(self.db_path.name, '0001.txt'))
+        self.assertEqual(chat_db.messages[1].file_path,
+                         pathlib.Path(self.db_path.name, '0002.yaml'))
+        self.assertEqual(chat_db.messages[2].file_path,
+                         pathlib.Path(self.db_path.name, '0003.txt'))
+        self.assertEqual(chat_db.messages[3].file_path,
+                         pathlib.Path(self.db_path.name, '0004.yaml'))
+
+    def test_chat_db_from_dir_glob(self) -> None:
+        chat_db = ChatDB.from_dir(pathlib.Path(self.cache_path.name),
+                                  pathlib.Path(self.db_path.name),
+                                  glob='*.txt')
+        self.assertEqual(len(chat_db.messages), 2)
+        self.assertEqual(chat_db.cache_path, pathlib.Path(self.cache_path.name))
+        self.assertEqual(chat_db.db_path, pathlib.Path(self.db_path.name))
+        self.assertEqual(chat_db.messages[0].file_path,
+                         pathlib.Path(self.db_path.name, '0001.txt'))
+        self.assertEqual(chat_db.messages[1].file_path,
+                         pathlib.Path(self.db_path.name, '0003.txt'))
+
+    def test_chat_db_filter(self) -> None:
+        chat_db = ChatDB.from_dir(pathlib.Path(self.cache_path.name),
+                                  pathlib.Path(self.db_path.name),
+                                  mfilter=MessageFilter(answer_contains='Answer 2'))
+        self.assertEqual(len(chat_db.messages), 1)
+        self.assertEqual(chat_db.cache_path, pathlib.Path(self.cache_path.name))
+        self.assertEqual(chat_db.db_path, pathlib.Path(self.db_path.name))
+        self.assertEqual(chat_db.messages[0].file_path,
+                         pathlib.Path(self.db_path.name, '0002.yaml'))
+        self.assertEqual(chat_db.messages[0].answer, 'Answer 2')
+
+    def test_chat_db_from_messges(self) -> None:
+        chat_db = ChatDB.from_messages(pathlib.Path(self.cache_path.name),
+                                       pathlib.Path(self.db_path.name),
+                                       messages=[self.message1, self.message2,
+                                                 self.message3, self.message4])
+        self.assertEqual(len(chat_db.messages), 4)
+        self.assertEqual(chat_db.cache_path, pathlib.Path(self.cache_path.name))
+        self.assertEqual(chat_db.db_path, pathlib.Path(self.db_path.name))
+
+    def test_chat_db_fids(self) -> None:
+        chat_db = ChatDB.from_dir(pathlib.Path(self.cache_path.name),
+                                  pathlib.Path(self.db_path.name))
+        self.assertEqual(chat_db.get_next_fid(), 1)
+        self.assertEqual(chat_db.get_next_fid(), 2)
+        self.assertEqual(chat_db.get_next_fid(), 3)
+        with open(chat_db.next_fname, 'r') as f:
+            self.assertEqual(f.read(), '3')
+
+    def test_chat_db_write(self) -> None:
+        # create a new ChatDB instance
+        chat_db = ChatDB.from_dir(pathlib.Path(self.cache_path.name),
+                                  pathlib.Path(self.db_path.name))
+        # check that Message.file_path is correct
+        self.assertEqual(chat_db.messages[0].file_path, pathlib.Path(self.db_path.name, '0001.txt'))
+        self.assertEqual(chat_db.messages[1].file_path, pathlib.Path(self.db_path.name, '0002.yaml'))
+        self.assertEqual(chat_db.messages[2].file_path, pathlib.Path(self.db_path.name, '0003.txt'))
+        self.assertEqual(chat_db.messages[3].file_path, pathlib.Path(self.db_path.name, '0004.yaml'))
+
+        # write the messages to the cache directory
+        chat_db.write_cache()
+        # check if the written files are in the cache directory
+        cache_dir_files = list(pathlib.Path(self.cache_path.name).glob('*'))
+        self.assertEqual(len(cache_dir_files), 4)
+        self.assertIn(pathlib.Path(self.cache_path.name, '0001.txt'), cache_dir_files)
+        self.assertIn(pathlib.Path(self.cache_path.name, '0002.yaml'), cache_dir_files)
+        self.assertIn(pathlib.Path(self.cache_path.name, '0003.txt'), cache_dir_files)
+        self.assertIn(pathlib.Path(self.cache_path.name, '0004.yaml'), cache_dir_files)
+        # check that Message.file_path has been correctly updated
+        self.assertEqual(chat_db.messages[0].file_path, pathlib.Path(self.cache_path.name, '0001.txt'))
+        self.assertEqual(chat_db.messages[1].file_path, pathlib.Path(self.cache_path.name, '0002.yaml'))
+        self.assertEqual(chat_db.messages[2].file_path, pathlib.Path(self.cache_path.name, '0003.txt'))
+        self.assertEqual(chat_db.messages[3].file_path, pathlib.Path(self.cache_path.name, '0004.yaml'))
+
+        # check the timestamp of the files in the DB directory
+        db_dir_files = list(pathlib.Path(self.db_path.name).glob('*'))
+        self.assertEqual(len(db_dir_files), 4)
+        old_timestamps = {file: file.stat().st_mtime for file in db_dir_files}
+        # overwrite the messages in the db directory
+        time.sleep(0.05)
+        chat_db.write_db()
+        # check if the written files are in the DB directory
+        db_dir_files = list(pathlib.Path(self.db_path.name).glob('*'))
+        self.assertEqual(len(db_dir_files), 4)
+        self.assertIn(pathlib.Path(self.db_path.name, '0001.txt'), db_dir_files)
+        self.assertIn(pathlib.Path(self.db_path.name, '0002.yaml'), db_dir_files)
+        self.assertIn(pathlib.Path(self.db_path.name, '0003.txt'), db_dir_files)
+        self.assertIn(pathlib.Path(self.db_path.name, '0004.yaml'), db_dir_files)
+        # check if all files in the DB dir have actually been overwritten
+        for file in db_dir_files:
+            self.assertGreater(file.stat().st_mtime, old_timestamps[file])
+        # check that Message.file_path has been correctly updated (again)
+        self.assertEqual(chat_db.messages[0].file_path, pathlib.Path(self.db_path.name, '0001.txt'))
+        self.assertEqual(chat_db.messages[1].file_path, pathlib.Path(self.db_path.name, '0002.yaml'))
+        self.assertEqual(chat_db.messages[2].file_path, pathlib.Path(self.db_path.name, '0003.txt'))
+        self.assertEqual(chat_db.messages[3].file_path, pathlib.Path(self.db_path.name, '0004.yaml'))

tests/test_message.py

@@ -2,7 +2,7 @@ import pathlib
 import tempfile
 from typing import cast
 from .test_main import CmmTestCase
-from chatmastermind.message import source_code, Message, MessageError, Question, Answer, AILine, ModelLine, MessageFilter
+from chatmastermind.message import source_code, Message, MessageError, Question, Answer, AILine, ModelLine, MessageFilter, message_in
 from chatmastermind.tags import Tag, TagLine
 
 
@@ -594,6 +594,12 @@ This is an answer.
         self.file_path_txt.unlink()
         self.file_yaml.close()
         self.file_path_yaml.unlink()
+        self.file_txt_no_tags.close
+        self.file_path_txt_no_tags.unlink()
+        self.file_txt_tags_empty.close
+        self.file_path_txt_tags_empty.unlink()
+        self.file_yaml_no_tags.close()
+        self.file_path_yaml_no_tags.unlink()
 
     def test_tags_from_file_txt(self) -> None:
         tags = Message.tags_from_file(self.file_path_txt)
@@ -671,6 +677,7 @@ class TagsFromDirTestCase(CmmTestCase):
 
     def tearDown(self) -> None:
         self.temp_dir.cleanup()
+        self.temp_dir_no_tags.cleanup()
 
     def test_tags_from_dir(self) -> None:
         all_tags = Message.tags_from_dir(pathlib.Path(self.temp_dir.name))
@@ -739,3 +746,32 @@ class MessageTagsStrTestCase(CmmTestCase):
 
     def test_tags_str(self) -> None:
         self.assertEqual(self.message.tags_str(), f'{TagLine.prefix} tag1')
+
+
+class MessageFilterTagsTestCase(CmmTestCase):
+    def setUp(self) -> None:
+        self.message = Message(Question('This is a question.'),
+                               tags={Tag('atag1'), Tag('btag2')},
+                               file_path=pathlib.Path('/tmp/foo/bla'))
+
+    def test_filter_tags(self) -> None:
+        tags_all = self.message.filter_tags()
+        self.assertSetEqual(tags_all, {Tag('atag1'), Tag('btag2')})
+        tags_pref = self.message.filter_tags(prefix='a')
+        self.assertSetEqual(tags_pref, {Tag('atag1')})
+        tags_cont = self.message.filter_tags(contain='2')
+        self.assertSetEqual(tags_cont, {Tag('btag2')})
+
+
+class MessageInTestCase(CmmTestCase):
+    def setUp(self) -> None:
+        self.message1 = Message(Question('This is a question.'),
+                                tags={Tag('atag1'), Tag('btag2')},
+                                file_path=pathlib.Path('/tmp/foo/bla'))
+        self.message2 = Message(Question('This is a question.'),
+                                tags={Tag('atag1'), Tag('btag2')},
+                                file_path=pathlib.Path('/tmp/bla/foo'))
+
+    def test_message_in(self) -> None:
+        self.assertTrue(message_in(self.message1, [self.message1]))
+        self.assertFalse(message_in(self.message1, [self.message2]))