Subject: Fixed an failing bpd test
 The failing test stems from differences in how the patch decorator
 from unitest works in python 3.14 in compassion to earlier versions. It
 does not patch code running in a multiprocessing.

Generally enhanced typehints in file.
Origin: https://github.com/beetbox/beets/commit/32cc47814e1f6329958b616b29b75cd86d0a9e7e
diff --git a/test/plugins/test_bpd.py b/test/plugins/test_bpd.py
index 16e424d7e..3798be6f1 100644
--- a/test/plugins/test_bpd.py
+++ b/test/plugins/test_bpd.py
@@ -21,7 +21,9 @@ import tempfile
 import threading
 import time
 import unittest
+from collections.abc import Iterator
 from contextlib import contextmanager
+from typing import Any, Literal, NamedTuple, overload
 from unittest.mock import MagicMock, patch
 
 import confuse
@@ -34,7 +36,7 @@ from beets.util import bluelet
 bpd = pytest.importorskip("beetsplug.bpd")
 
 
-class CommandParseTest(unittest.TestCase):
+class TestCommandParse:
     def test_no_args(self):
         s = r"command"
         c = bpd.Command(s)
@@ -76,14 +78,28 @@ class CommandParseTest(unittest.TestCase):
         assert c.args == ["hello \\ there"]
 
 
+class ErrorData(NamedTuple):
+    code: int
+    pos: int
+    cmd: str
+    msg: str
+
+
 class MPCResponse:
-    def __init__(self, raw_response):
+    ok: bool
+    data: dict[str, str | list[str]]
+    err_data: None | ErrorData
+
+    def __init__(self, raw_response: bytes):
         body = b"\n".join(raw_response.split(b"\n")[:-2]).decode("utf-8")
         self.data = self._parse_body(body)
         status = raw_response.split(b"\n")[-2].decode("utf-8")
         self.ok, self.err_data = self._parse_status(status)
 
-    def _parse_status(self, status):
+    @staticmethod
+    def _parse_status(
+        status: str,
+    ) -> tuple[Literal[True], None] | tuple[Literal[False], ErrorData]:
         """Parses the first response line, which contains the status."""
         if status.startswith("OK") or status.startswith("list_OK"):
             return True, None
@@ -91,17 +107,18 @@ class MPCResponse:
             code, rest = status[5:].split("@", 1)
             pos, rest = rest.split("]", 1)
             cmd, rest = rest[2:].split("}")
-            return False, (int(code), int(pos), cmd, rest[1:])
+            return False, ErrorData(int(code), int(pos), cmd, rest[1:])
         else:
             raise RuntimeError(f"Unexpected status: {status!r}")
 
-    def _parse_body(self, body):
+    @staticmethod
+    def _parse_body(body: str) -> dict[str, str | list[str]]:
         """Messages are generally in the format "header: content".
         Convert them into a dict, storing the values for repeated headers as
         lists of strings, and non-repeated ones as string.
         """
-        data = {}
-        repeated_headers = set()
+        data: dict[str, str | list[str]] = {}
+        repeated_headers: set[str] = set()
         for line in body.split("\n"):
             if not line:
                 continue
@@ -110,9 +127,9 @@ class MPCResponse:
             header, content = line.split(":", 1)
             content = content.lstrip()
             if header in repeated_headers:
-                data[header].append(content)
+                data[header].append(content)  # type: ignore
             elif header in data:
-                data[header] = [data[header], content]
+                data[header] = [data[header], content]  # type: ignore[list-item]
                 repeated_headers.add(header)
             else:
                 data[header] = content
@@ -120,7 +137,10 @@ class MPCResponse:
 
 
 class MPCClient:
-    def __init__(self, sock, do_hello=True):
+    sock: socket.socket
+    buf: bytes
+
+    def __init__(self, sock: socket.socket, do_hello: bool = True):
         self.sock = sock
         self.buf = b""
         if do_hello:
@@ -128,19 +148,25 @@ class MPCClient:
             if not hello.ok:
                 raise RuntimeError("Bad hello")
 
-    def get_response(self, force_multi=None):
+    @overload
+    def get_response(self, force_multi: None = None) -> MPCResponse: ...
+    @overload
+    def get_response(self, force_multi: int) -> list[MPCResponse | None]: ...
+    def get_response(
+        self, force_multi: int | None = None
+    ) -> MPCResponse | list[MPCResponse | None]:
         """Wait for a full server response and wrap it in a helper class.
         If the request was a batch request then this will return a list of
         `MPCResponse`s, one for each processed subcommand.
         """
 
-        response = b""
-        responses = []
+        response: bytes = b""
+        responses: list[MPCResponse | None] = []
         while True:
             line = self.readline()
             response += line
             if line.startswith(b"OK") or line.startswith(b"ACK"):
-                if force_multi or any(responses):
+                if isinstance(force_multi, int):
                     if line.startswith(b"ACK"):
                         responses.append(MPCResponse(response))
                         n_remaining = force_multi - len(responses)
@@ -154,7 +180,7 @@ class MPCClient:
             elif not line:
                 raise RuntimeError(f"Unexpected response: {line!r}")
 
-    def serialise_command(self, command, *args):
+    def serialise_command(self, command: str, *args: str) -> bytes:
         cmd = [command.encode("utf-8")]
         for arg in [a.encode("utf-8") for a in args]:
             if b" " in arg:
@@ -163,12 +189,12 @@ class MPCClient:
                 cmd.append(arg)
         return b" ".join(cmd) + b"\n"
 
-    def send_command(self, command, *args):
+    def send_command(self, command: str, *args: str) -> MPCResponse:
         request = self.serialise_command(command, *args)
         self.sock.sendall(request)
         return self.get_response()
 
-    def send_commands(self, *commands):
+    def send_commands(self, *commands: str) -> list[MPCResponse]:
         """Use MPD command batching to send multiple commands at once.
         Each item of commands is a tuple containing a command followed by
         any arguments.
@@ -183,9 +209,9 @@ class MPCClient:
         requests.append(b"command_list_end\n")
         request = b"".join(requests)
         self.sock.sendall(request)
-        return self.get_response(force_multi=len(commands))
+        return list(filter(None, self.get_response(force_multi=len(commands))))
 
-    def readline(self, terminator=b"\n", bufsize=1024):
+    def readline(self, terminator: bytes = b"\n", bufsize: int = 1024) -> bytes:
         """Reads a line of data from the socket."""
 
         while True:
@@ -203,7 +229,7 @@ class MPCClient:
                 return line
 
 
-def implements(commands, fail=False):
+def implements(commands: set[str], fail=False):
     def _test(self):
         with self.run_bpd() as client:
             response = client.send_command("commands")
@@ -221,8 +247,17 @@ bluelet_listener = bluelet.Listener
 def start_server(args, assigned_port, listener_patch):
     """Start the bpd server, writing the port to `assigned_port`."""
 
+    # FIXME: This is used in the test_cmd_decoders test. Patch does not apply to
+    # code running in mp.Process anymore (change in 3.14)
+    # There might be a better way to fix this but as I have already spent
+    # way more time here than planned this seems like the easiest way forward
+    patch(
+        "beetsplug.bpd.gstplayer.GstPlayer.get_decoders",
+        MagicMock(return_value={"default": ({"audio/mpeg"}, {"mp3"})}),
+    ).start()
+
     def listener_wrap(host, port):
-        """Wrap `bluelet.Listener`, writing the port to `assigend_port`."""
+        """Wrap `bluelet.Listener`, writing the port to `assigned_port`."""
         # `bluelet.Listener` has previously been saved to
         # `bluelet_listener` as this function will replace it at its
         # original location.
@@ -259,19 +294,16 @@ class BPDTestHelper(PluginTestCase):
         self.lib.add_album([self.item1, self.item2])
 
     @contextmanager
-    def run_bpd(
+    def bpd_server(
         self,
-        host="localhost",
-        password=None,
-        do_hello=True,
-        second_client=False,
-    ):
+        host: str = "localhost",
+        password: str | None = None,
+    ) -> Iterator[tuple[str, int]]:
         """Runs BPD in another process, configured with the same library
-        database as we created in the setUp method. Exposes a client that is
-        connected to the server, and kills the server at the end.
+        database as we created in the setUp method. Kills the server at the end.
         """
         # Create a config file:
-        config = {
+        config: dict[str, Any] = {
             "pluginpath": [str(self.temp_dir_path)],
             "plugins": "bpd",
             # use port 0 to let the OS choose a free port
@@ -291,7 +323,10 @@ class BPDTestHelper(PluginTestCase):
         config_file.close()
 
         # Fork and launch BPD in the new process:
-        assigned_port = mp.Queue(2)  # 2 slots, `control_port` and `port`
+        assigned_port: mp.Queue[int] = mp.Queue(
+            2
+        )  # 2 slots, `control_port` and `port`
+
         server = mp.Process(
             target=start_server,
             args=(
@@ -310,32 +345,48 @@ class BPDTestHelper(PluginTestCase):
         server.start()
 
         try:
-            assigned_port.get(timeout=1)  # skip control_port
-            port = assigned_port.get(timeout=0.5)  # read port
-
-            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-            try:
-                sock.connect((host, port))
-
-                if second_client:
-                    sock2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-                    try:
-                        sock2.connect((host, port))
-                        yield (
-                            MPCClient(sock, do_hello),
-                            MPCClient(sock2, do_hello),
-                        )
-                    finally:
-                        sock2.close()
-
-                else:
-                    yield MPCClient(sock, do_hello)
-            finally:
-                sock.close()
+            assigned_port.get(timeout=5)  # skip control_port
+            port = assigned_port.get(timeout=2)  # read port
+            yield (host, port)
         finally:
             server.terminate()
             server.join(timeout=0.2)
 
+    @contextmanager
+    def bpd_client(
+        self,
+        host: str,
+        port: int,
+        do_hello: bool = True,
+    ) -> Iterator[MPCClient]:
+        """Connects a BPD client to a given server"""
+
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        try:
+            sock.connect((host, port))
+            yield MPCClient(sock, do_hello)
+        finally:
+            sock.close()
+
+    @contextmanager
+    def run_bpd(
+        self,
+        host: str = "localhost",
+        password: str | None = None,
+        do_hello: bool = True,
+    ) -> Iterator[MPCClient]:
+        """Runs BPD in another process, configured with the same library
+        database as we created in the setUp method. Exposes a client that is
+        connected to the server, and kills the server at the end.
+        """
+
+        with self.bpd_server(
+            host,
+            password,
+        ) as (host, port):
+            with self.bpd_client(host, port, do_hello) as client:
+                yield client
+
     def _assert_ok(self, *responses):
         for response in responses:
             assert response is not None
@@ -488,22 +539,30 @@ class BPDQueryTest(BPDTestHelper):
                 if any(not r.ok for r in rs):
                     raise RuntimeError("Toggler failed")
 
-        with self.run_bpd(second_client=True) as (client, client2):
-            self._bpd_add(client, self.item1, self.item2)
-            toggler = threading.Thread(target=_toggle, args=(client2,))
-            toggler.start()
-            # Idling will hang until the toggler thread changes the play state.
-            # Since the client sockets have a 1s timeout set at worst this will
-            # raise a socket.timeout and fail the test if the toggler thread
-            # manages to finish before the idle command is sent here.
-            response = client.send_command("idle", "player")
-            toggler.join()
+        with self.bpd_server() as (host, port):
+            with (
+                self.bpd_client(host, port) as client1,
+                self.bpd_client(host, port) as client2,
+            ):
+                self._bpd_add(client1, self.item1, self.item2)
+                toggler = threading.Thread(target=_toggle, args=(client2,))
+                toggler.start()
+                # Idling will hang until the toggler thread changes the play state.
+                # Since the client sockets have a 1s timeout set at worst this will
+                # raise a socket.timeout and fail the test if the toggler thread
+                # manages to finish before the idle command is sent here.
+                response = client1.send_command("idle", "player")
+                toggler.join()
         self._assert_ok(response)
 
     def test_cmd_idle_with_pending(self):
-        with self.run_bpd(second_client=True) as (client, client2):
-            response1 = client.send_command("random", "1")
-            response2 = client2.send_command("idle")
+        with self.bpd_server() as (host, port):
+            with (
+                self.bpd_client(host, port) as client1,
+                self.bpd_client(host, port) as client2,
+            ):
+                response1 = client1.send_command("random", "1")
+                response2 = client2.send_command("idle")
         self._assert_ok(response1, response2)
         assert "options" == response2.data["changed"]
 
@@ -1130,10 +1189,6 @@ class BPDReflectionTest(BPDTestHelper):
         fail=True,
     )
 
-    @patch(
-        "beetsplug.bpd.gstplayer.GstPlayer.get_decoders",
-        MagicMock(return_value={"default": ({"audio/mpeg"}, {"mp3"})}),
-    )
     def test_cmd_decoders(self):
         with self.run_bpd() as client:
             response = client.send_command("decoders")