diff --git a/tests/test_init_opts.py b/tests/test_init_opts.py
new file mode 100644
index 0000000..7927ab1
--- /dev/null
+++ b/tests/test_init_opts.py
@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from src import boot
+from types import GenericAlias
+from typing import NotRequired
+from src.boot import SyncplayOptions
+
+
+def test_options():
+    """
+    Verify types and structure of SyncplayOptions and DESC.
+    """
+    assert len(SyncplayOptions.__annotations__) == len(boot.DESC)
+    assert set(SyncplayOptions.__annotations__) == set(boot.DESC)
+
+    for tag, desc in boot.DESC.values():
+        assert tag is None or type(tag) is str
+        assert type(desc) is str
+
+    for field in SyncplayOptions.__annotations__.values():
+        assert field.__origin__ is NotRequired
+        assert len(field.__args__) == 1
+
+        if type(field_t := field.__args__[0]) is GenericAlias:
+            assert field_t.__origin__ is list
+            assert len(field_t.__args__) == 1
+            field_t = field_t.__args__[0]
+
+        assert field_t in (int, str, bool)
+
+
+def verify_env_opts():
+    """
+    Verify the ENV_OPTS with expected environment variable options.
+    """
+    expected_opts = {
+        'config': str,  # only non-list options
+        'port': int,
+        'password': str,
+        'motd': str,
+        'salt': str,
+        'random_salt': bool,
+        'isolate_rooms': bool,
+        'disable_chat': bool,
+        'disable_ready': bool,
+        'enable_stats': bool,
+        'enable_tls': bool,
+        'persistent': bool,
+        'max_username': int,
+        'max_chat_message': int,
+        'listen_ipv4': str,
+        'listen_ipv6': str,
+    }
+    assert boot.ENV_OPTS == expected_opts
+
+
+def verify_cfg_opts():
+    """
+    Verify the CFG_OPTS with expected configure file options.
+    """
+    expected_opts = {
+        'config': (str, False),  # (type, is_list)
+        'port': (int, False),
+        'password': (str, False),
+        'motd': (str, False),
+        'salt': (str, False),
+        'random_salt': (bool, False),
+        'isolate_rooms': (bool, False),
+        'disable_chat': (bool, False),
+        'disable_ready': (bool, False),
+        'enable_stats': (bool, False),
+        'enable_tls': (bool, False),
+        'persistent': (bool, False),
+        'max_username': (int, False),
+        'max_chat_message': (int, False),
+        'permanent_rooms': (str, True),
+        'listen_ipv4': (str, False),
+        'listen_ipv6': (str, False),
+    }
+    assert boot.CFG_OPTS == expected_opts
+
+
+def verify_arg_opts():
+    """
+    Verify the ARG_OPTS with expected command line options.
+    """
+    expected_opts = {
+        'config': {'type': str, 'metavar': 'FILE'},  # argparse options
+        'port': {'type': int, 'metavar': 'PORT'},
+        'password': {'type': str, 'metavar': 'PASSWD'},
+        'motd': {'type': str, 'metavar': 'MESSAGE'},
+        'salt': {'type': str, 'metavar': 'TEXT'},
+        'random_salt': {'action': 'store_true'},
+        'isolate_rooms': {'action': 'store_true'},
+        'disable_chat': {'action': 'store_true'},
+        'disable_ready': {'action': 'store_true'},
+        'enable_stats': {'action': 'store_true'},
+        'enable_tls': {'action': 'store_true'},
+        'persistent': {'action': 'store_true'},
+        'max_username': {'type': int, 'metavar': 'NUM'},
+        'max_chat_message': {'type': int, 'metavar': 'NUM'},
+        'permanent_rooms': {'type': str, 'metavar': 'ROOM', 'nargs': '*'},
+        'listen_ipv4': {'type': str, 'metavar': 'ADDR'},
+        'listen_ipv6': {'type': str, 'metavar': 'ADDR'},
+    }
+    for tag, opts in expected_opts.items():
+        _, opts['help'] = boot.DESC[tag]  # help message from DESC
+
+    assert boot.ARG_OPTS == expected_opts
+
+
+def test_init_opts():
+    """
+    Test initialization and idempotency of the init_opts function.
+    """
+    assert not boot.ARG_OPTS
+    assert not boot.ENV_OPTS
+    assert not boot.CFG_OPTS
+
+    for _ in range(2):
+        boot.init_opts()  # run twice to verify idempotency
+        verify_arg_opts()
+        verify_env_opts()
+        verify_cfg_opts()