diff --git a/tests/commands/test_cmd_command.py b/tests/commands/test_cmd_command.py
index 28565c2..4a7c4a4 100644
--- a/tests/commands/test_cmd_command.py
+++ b/tests/commands/test_cmd_command.py
@@ -37,5 +37,31 @@ class TestCmdCommand:
         result = await cmd.execute(msg)
         assert result is True
         call_args = command_mock_bot.command_manager.send_response.call_args
+        assert call_args is not None
         response = call_args[0][1]
         assert "ping" in response or "help" in response or "cmd" in response
+
+    def test_get_commands_list_truncation(self, command_mock_bot):
+        """Test that _get_commands_list truncates long lists with '(N more)' suffix."""
+        import re
+        command_mock_bot.config.add_section("Cmd_Command")
+        command_mock_bot.config.set("Cmd_Command", "enabled", "true")
+        command_mock_bot.command_manager.keywords = {}
+        # Create 25 mock commands with long names to force truncation
+        commands = {}
+        for i in range(25):
+            name = f"longcommandname{i:02d}"
+            mock_cmd = type("MockCmd", (), {"keywords": [name]})()
+            commands[name] = mock_cmd
+        command_mock_bot.command_manager.commands = commands
+        cmd = CmdCommand(command_mock_bot)
+        # "Available commands: " = 20 chars; "longcommandnameNN" = 17 chars; ", " = 2 chars
+        # 3 commands fit in 75 chars; suffix " (22 more)" = 11 chars; total = 86
+        # max_length=90 allows 3 commands + suffix, but not a 4th command
+        result = cmd._get_commands_list(max_length=90)
+        # Should contain truncation indicator
+        assert "more)" in result
+        # Should start with prefix
+        assert result.startswith("Available commands: ")
+        # Should NOT contain doubled numbers like "(5 5 more)"
+        assert not re.search(r'\(\d+ \d+ more\)', result)
diff --git a/tests/commands/test_hello_command.py b/tests/commands/test_hello_command.py
index a0cb1ac..43caf77 100644
--- a/tests/commands/test_hello_command.py
+++ b/tests/commands/test_hello_command.py
@@ -43,8 +43,7 @@ class TestHelloCommand:
         cmd = HelloCommand(command_mock_bot)
         with patch("modules.commands.hello_command.random.choice", side_effect=lambda x: x[0]):
             result = cmd.get_random_greeting()
-        assert result
-        assert isinstance(result, str)
+        assert isinstance(result, str) and len(result) > 0
 
     def test_get_emoji_response_vulcan(self, command_mock_bot):
         command_mock_bot.config.add_section("Hello_Command")
@@ -78,5 +77,6 @@ class TestHelloCommand:
             result = await cmd.execute(msg)
         assert result is True
         call_args = command_mock_bot.command_manager.send_response.call_args
+        assert call_args is not None
         response = call_args[0][1]
-        assert response
+        assert isinstance(response, str) and len(response) > 0
diff --git a/tests/commands/test_help_command.py b/tests/commands/test_help_command.py
index 3611cff..4ac7d98 100644
--- a/tests/commands/test_help_command.py
+++ b/tests/commands/test_help_command.py
@@ -31,3 +31,5 @@ class TestHelpCommand:
         msg = mock_message(content="help", is_dm=True)
         result = await cmd.execute(msg)
         assert result is True
+        # Note: HelpCommand.execute() is a placeholder; actual help logic is in
+        # CommandManager.check_keywords(). Response sending is tested there.
diff --git a/tests/commands/test_magic8_command.py b/tests/commands/test_magic8_command.py
index 4470272..be31706 100644
--- a/tests/commands/test_magic8_command.py
+++ b/tests/commands/test_magic8_command.py
@@ -32,6 +32,7 @@ class TestMagic8Command:
         result = await cmd.execute(msg)
         assert result is True
         call_args = command_mock_bot.command_manager.send_response.call_args
+        assert call_args is not None
         response = call_args[0][1]
         assert "🎱" in response
         assert any(r in response for r in magic8_responses)
@@ -45,5 +46,6 @@ class TestMagic8Command:
         result = await cmd.execute(msg)
         assert result is True
         call_args = command_mock_bot.command_manager.send_response.call_args
+        assert call_args is not None
         response = call_args[0][1]
         assert "Alice" in response or "@[" in response
diff --git a/tests/commands/test_roll_command.py b/tests/commands/test_roll_command.py
index 057285f..d66cad1 100644
--- a/tests/commands/test_roll_command.py
+++ b/tests/commands/test_roll_command.py
@@ -54,6 +54,7 @@ class TestRollCommandExecute:
         result = await cmd.execute(msg)
         assert result is True
         call_args = command_mock_bot.command_manager.send_response.call_args
+        assert call_args is not None
         response = call_args[0][1]
         # Should be a number between 1 and 100
         nums = re.findall(r'\d+', response)
@@ -70,6 +71,7 @@ class TestRollCommandExecute:
         result = await cmd.execute(msg)
         assert result is True
         call_args = command_mock_bot.command_manager.send_response.call_args
+        assert call_args is not None
         response = call_args[0][1]
         nums = re.findall(r'\d+', response)
         assert len(nums) >= 1
diff --git a/tests/test_channel_manager_logic.py b/tests/test_channel_manager_logic.py
new file mode 100644
index 0000000..f21a6d1
--- /dev/null
+++ b/tests/test_channel_manager_logic.py
@@ -0,0 +1,80 @@
+"""Tests for ChannelManager pure logic (no meshcore device calls)."""
+
+import hashlib
+
+import pytest
+from unittest.mock import Mock
+
+from modules.channel_manager import ChannelManager
+
+
+@pytest.fixture
+def cm(mock_logger):
+    """ChannelManager with mock bot for pure logic tests."""
+    bot = Mock()
+    bot.logger = mock_logger
+    bot.db_manager = Mock()
+    bot.db_manager.db_path = "/dev/null"
+    bot.connected = False
+    bot.meshcore = Mock()
+    bot.meshcore.channels = {}
+    return ChannelManager(bot, max_channels=8)
+
+
+class TestGenerateHashtagKey:
+    """Tests for generate_hashtag_key() static method."""
+
+    def test_deterministic(self):
+        key1 = ChannelManager.generate_hashtag_key("general")
+        key2 = ChannelManager.generate_hashtag_key("general")
+        assert key1 == key2
+        assert len(key1) == 16
+
+    def test_prepends_hash_if_missing(self):
+        key_without = ChannelManager.generate_hashtag_key("general")
+        key_with = ChannelManager.generate_hashtag_key("#general")
+        assert key_without == key_with
+
+    def test_known_value(self):
+        """Verify against independently computed SHA256."""
+        expected = hashlib.sha256(b"#longfast").digest()[:16]
+        result = ChannelManager.generate_hashtag_key("#LongFast")
+        assert result == expected
+
+
+class TestChannelNameLookup:
+    """Tests for get_channel_name()."""
+
+    def test_cached_channel_name(self, cm):
+        cm._channels_cache = {0: {"channel_name": "general"}}
+        cm._cache_valid = True
+        assert cm.get_channel_name(0) == "general"
+
+    def test_not_cached_returns_fallback(self, cm):
+        cm._channels_cache = {}
+        cm._cache_valid = True
+        result = cm.get_channel_name(99)
+        assert "99" in result
+
+
+class TestChannelNumberLookup:
+    """Tests for get_channel_number()."""
+
+    def test_found_by_name(self, cm):
+        cm._channels_cache = {0: {"channel_name": "general"}, 1: {"channel_name": "test"}}
+        cm._cache_valid = True
+        assert cm.get_channel_number("test") == 1
+
+    def test_case_insensitive(self, cm):
+        cm._channels_cache = {0: {"channel_name": "General"}}
+        cm._cache_valid = True
+        assert cm.get_channel_number("general") == 0
+
+
+class TestCacheManagement:
+    """Tests for cache invalidation."""
+
+    def test_invalidate_cache(self, cm):
+        cm._cache_valid = True
+        cm.invalidate_cache()
+        assert cm._cache_valid is False
diff --git a/tests/test_command_manager.py b/tests/test_command_manager.py
new file mode 100644
index 0000000..d9200c5
--- /dev/null
+++ b/tests/test_command_manager.py
@@ -0,0 +1,274 @@
+"""Tests for modules.command_manager."""
+
+import time
+
+import pytest
+from configparser import ConfigParser
+from unittest.mock import Mock, MagicMock, patch, AsyncMock
+
+from modules.command_manager import CommandManager, InternetStatusCache
+from modules.models import MeshMessage
+from tests.conftest import mock_message
+
+
+@pytest.fixture
+def cm_bot(mock_logger):
+    """Mock bot for CommandManager tests."""
+    bot = Mock()
+    bot.logger = mock_logger
+    bot.config = ConfigParser()
+    bot.config.add_section("Bot")
+    bot.config.set("Bot", "bot_name", "TestBot")
+    bot.config.add_section("Channels")
+    bot.config.set("Channels", "monitor_channels", "general,test")
+    bot.config.set("Channels", "respond_to_dms", "true")
+    bot.config.add_section("Keywords")
+    bot.config.set("Keywords", "ping", "Pong!")
+    bot.config.set("Keywords", "test", "ack")
+    bot.translator = Mock()
+    # Translator returns "key: kwarg_values" so assertions can check content
+    bot.translator.translate = Mock(
+        side_effect=lambda key, **kw: f"{key}: {' '.join(str(v) for v in kw.values())}"
+    )
+    bot.meshcore = None
+    bot.rate_limiter = Mock()
+    bot.rate_limiter.can_send = Mock(return_value=True)
+    bot.bot_tx_rate_limiter = Mock()
+    bot.bot_tx_rate_limiter.wait_for_tx = Mock()
+    bot.tx_delay_ms = 0
+    return bot
+
+
+def make_manager(bot, commands=None):
+    """Create CommandManager with mocked PluginLoader."""
+    with patch("modules.command_manager.PluginLoader") as mock_loader_class:
+        mock_loader = Mock()
+        mock_loader.load_all_plugins = Mock(return_value=commands or {})
+        mock_loader_class.return_value = mock_loader
+        return CommandManager(bot)
+
+
+class TestLoadKeywords:
+    """Tests for keyword loading from config."""
+
+    def test_load_keywords_from_config(self, cm_bot):
+        manager = make_manager(cm_bot)
+        assert manager.keywords["ping"] == "Pong!"
+        assert manager.keywords["test"] == "ack"
+
+    def test_load_keywords_strips_quotes(self, cm_bot):
+        cm_bot.config.set("Keywords", "quoted", '"Hello World"')
+        manager = make_manager(cm_bot)
+        assert manager.keywords["quoted"] == "Hello World"
+
+    def test_load_keywords_decodes_escapes(self, cm_bot):
+        cm_bot.config.set("Keywords", "multiline", r"Line1\nLine2")
+        manager = make_manager(cm_bot)
+        assert "\n" in manager.keywords["multiline"]
+
+    def test_load_keywords_empty_section(self, cm_bot):
+        cm_bot.config.remove_section("Keywords")
+        cm_bot.config.add_section("Keywords")
+        manager = make_manager(cm_bot)
+        assert manager.keywords == {}
+
+
+class TestLoadBannedUsers:
+    """Tests for banned users loading."""
+
+    def test_load_banned_users_from_config(self, cm_bot):
+        cm_bot.config.add_section("Banned_Users")
+        cm_bot.config.set("Banned_Users", "banned_users", "BadUser1, BadUser2")
+        manager = make_manager(cm_bot)
+        assert "BadUser1" in manager.banned_users
+        assert "BadUser2" in manager.banned_users
+
+    def test_load_banned_users_empty(self, cm_bot):
+        manager = make_manager(cm_bot)
+        assert manager.banned_users == []
+
+    def test_load_banned_users_whitespace_handling(self, cm_bot):
+        cm_bot.config.add_section("Banned_Users")
+        cm_bot.config.set("Banned_Users", "banned_users", "  user1 , user2  ")
+        manager = make_manager(cm_bot)
+        assert "user1" in manager.banned_users
+        assert "user2" in manager.banned_users
+
+
+class TestIsUserBanned:
+    """Tests for ban checking logic."""
+
+    def test_exact_match(self, cm_bot):
+        cm_bot.config.add_section("Banned_Users")
+        cm_bot.config.set("Banned_Users", "banned_users", "BadUser")
+        manager = make_manager(cm_bot)
+        assert manager.is_user_banned("BadUser") is True
+
+    def test_prefix_match(self, cm_bot):
+        cm_bot.config.add_section("Banned_Users")
+        cm_bot.config.set("Banned_Users", "banned_users", "BadUser")
+        manager = make_manager(cm_bot)
+        assert manager.is_user_banned("BadUser 123") is True
+
+    def test_no_match(self, cm_bot):
+        cm_bot.config.add_section("Banned_Users")
+        cm_bot.config.set("Banned_Users", "banned_users", "BadUser")
+        manager = make_manager(cm_bot)
+        assert manager.is_user_banned("GoodUser") is False
+
+    def test_none_sender(self, cm_bot):
+        manager = make_manager(cm_bot)
+        assert manager.is_user_banned(None) is False
+
+
+class TestChannelTriggerAllowed:
+    """Tests for _is_channel_trigger_allowed."""
+
+    def test_dm_always_allowed(self, cm_bot):
+        cm_bot.config.set("Channels", "channel_keywords", "ping")
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="wx", is_dm=True)
+        assert manager._is_channel_trigger_allowed("wx", msg) is True
+
+    def test_none_whitelist_allows_all(self, cm_bot):
+        manager = make_manager(cm_bot)
+        assert manager.channel_keywords is None
+        msg = mock_message(content="anything", channel="general", is_dm=False)
+        assert manager._is_channel_trigger_allowed("anything", msg) is True
+
+    def test_whitelist_allows_listed(self, cm_bot):
+        cm_bot.config.set("Channels", "channel_keywords", "ping, help")
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="ping", channel="general", is_dm=False)
+        assert manager._is_channel_trigger_allowed("ping", msg) is True
+
+    def test_whitelist_blocks_unlisted(self, cm_bot):
+        cm_bot.config.set("Channels", "channel_keywords", "ping, help")
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="wx", channel="general", is_dm=False)
+        assert manager._is_channel_trigger_allowed("wx", msg) is False
+
+
+class TestLoadMonitorChannels:
+    """Tests for monitor channels loading."""
+
+    def test_load_monitor_channels(self, cm_bot):
+        manager = make_manager(cm_bot)
+        assert "general" in manager.monitor_channels
+        assert "test" in manager.monitor_channels
+        assert len(manager.monitor_channels) == 2
+
+    def test_load_monitor_channels_empty(self, cm_bot):
+        cm_bot.config.set("Channels", "monitor_channels", "")
+        manager = make_manager(cm_bot)
+        assert manager.monitor_channels == []
+
+
+class TestLoadChannelKeywords:
+    """Tests for channel keyword whitelist loading."""
+
+    def test_load_channel_keywords_returns_list(self, cm_bot):
+        cm_bot.config.set("Channels", "channel_keywords", "ping, wx, help")
+        manager = make_manager(cm_bot)
+        assert isinstance(manager.channel_keywords, list)
+        assert "ping" in manager.channel_keywords
+        assert "wx" in manager.channel_keywords
+        assert "help" in manager.channel_keywords
+
+    def test_load_channel_keywords_empty_returns_none(self, cm_bot):
+        cm_bot.config.set("Channels", "channel_keywords", "")
+        manager = make_manager(cm_bot)
+        assert manager.channel_keywords is None
+
+    def test_load_channel_keywords_not_set_returns_none(self, cm_bot):
+        manager = make_manager(cm_bot)
+        assert manager.channel_keywords is None
+
+
+class TestCheckKeywords:
+    """Tests for check_keywords() message matching."""
+
+    def test_exact_keyword_match(self, cm_bot):
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="ping", channel="general", is_dm=False)
+        matches = manager.check_keywords(msg)
+        assert any(trigger == "ping" for trigger, _ in matches)
+
+    def test_prefix_required_blocks_bare_keyword(self, cm_bot):
+        cm_bot.config.set("Bot", "command_prefix", "!")
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="ping", channel="general", is_dm=False)
+        matches = manager.check_keywords(msg)
+        assert len(matches) == 0
+
+    def test_prefix_matches(self, cm_bot):
+        cm_bot.config.set("Bot", "command_prefix", "!")
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="!ping", channel="general", is_dm=False)
+        matches = manager.check_keywords(msg)
+        assert any(trigger == "ping" for trigger, _ in matches)
+
+    def test_wrong_channel_no_match(self, cm_bot):
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="ping", channel="other", is_dm=False)
+        matches = manager.check_keywords(msg)
+        assert len(matches) == 0
+
+    def test_dm_allowed(self, cm_bot):
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="ping", is_dm=True)
+        matches = manager.check_keywords(msg)
+        assert any(trigger == "ping" for trigger, _ in matches)
+
+    def test_help_routing(self, cm_bot):
+        manager = make_manager(cm_bot)
+        msg = mock_message(content="help", is_dm=True)
+        matches = manager.check_keywords(msg)
+        assert any(trigger == "help" for trigger, _ in matches)
+
+
+class TestGetHelpForCommand:
+    """Tests for command-specific help."""
+
+    def test_known_command_returns_help(self, cm_bot):
+        mock_cmd = MagicMock()
+        mock_cmd.keywords = ["wx"]
+        mock_cmd.get_help_text = Mock(return_value="Weather forecast info")
+        mock_cmd.dm_only = False
+        mock_cmd.requires_internet = False
+        manager = make_manager(cm_bot, commands={"wx": mock_cmd})
+        result = manager.get_help_for_command("wx")
+        # Translator receives help_text as kwarg, so it appears in the output
+        assert "Weather forecast info" in result
+        # Verify translator was called with the right key
+        cm_bot.translator.translate.assert_called_with(
+            "commands.help.specific", command="wx", help_text="Weather forecast info"
+        )
+
+    def test_unknown_command_returns_error(self, cm_bot):
+        manager = make_manager(cm_bot)
+        result = manager.get_help_for_command("nonexistent")
+        # Translator receives 'commands.help.unknown' key with command name
+        cm_bot.translator.translate.assert_called()
+        call_args = cm_bot.translator.translate.call_args
+        assert call_args[0][0] == "commands.help.unknown"
+        assert call_args[1]["command"] == "nonexistent"
+
+
+class TestInternetStatusCache:
+    """Tests for InternetStatusCache."""
+
+    def test_is_valid_fresh(self):
+        cache = InternetStatusCache(has_internet=True, timestamp=time.time())
+        assert cache.is_valid(30) is True
+
+    def test_is_valid_stale(self):
+        cache = InternetStatusCache(has_internet=True, timestamp=time.time() - 60)
+        assert cache.is_valid(30) is False
+
+    def test_get_lock_lazy_creation(self):
+        cache = InternetStatusCache(has_internet=True, timestamp=0)
+        assert cache._lock is None
+        lock1 = cache._get_lock()
+        lock2 = cache._get_lock()
+        assert lock1 is lock2
diff --git a/tests/test_db_manager.py b/tests/test_db_manager.py
new file mode 100644
index 0000000..582f172
--- /dev/null
+++ b/tests/test_db_manager.py
@@ -0,0 +1,182 @@
+"""Tests for modules.db_manager."""
+
+import sqlite3
+import json
+
+import pytest
+from unittest.mock import Mock
+
+from modules.db_manager import DBManager
+
+
+@pytest.fixture
+def db(mock_logger, tmp_path):
+    """File-based DBManager for testing. _init_database() auto-creates core tables."""
+    bot = Mock()
+    bot.logger = mock_logger
+    return DBManager(bot, str(tmp_path / "test.db"))
+
+
+class TestGeocoding:
+    """Tests for geocoding cache."""
+
+    def test_cache_and_retrieve_geocoding(self, db):
+        db.cache_geocoding("Seattle, WA", 47.6062, -122.3321)
+        lat, lon = db.get_cached_geocoding("Seattle, WA")
+        assert abs(lat - 47.6062) < 0.001
+        assert abs(lon - (-122.3321)) < 0.001
+
+    def test_get_cached_geocoding_miss(self, db):
+        lat, lon = db.get_cached_geocoding("Nonexistent City")
+        assert lat is None
+        assert lon is None
+
+    def test_cache_geocoding_overwrites_existing(self, db):
+        db.cache_geocoding("Test", 10.0, 20.0)
+        db.cache_geocoding("Test", 30.0, 40.0)
+        lat, lon = db.get_cached_geocoding("Test")
+        assert abs(lat - 30.0) < 0.001
+        assert abs(lon - 40.0) < 0.001
+
+    def test_cache_geocoding_invalid_hours_logged(self, db):
+        """Invalid cache_hours is caught and logged, not raised."""
+        db.cache_geocoding("Test", 10.0, 20.0, cache_hours=0)
+        db.bot.logger.error.assert_called()
+        # Verify it did not store anything
+        lat, lon = db.get_cached_geocoding("Test")
+        assert lat is None
+
+
+class TestGenericCache:
+    """Tests for generic cache."""
+
+    def test_cache_and_retrieve_value(self, db):
+        db.cache_value("weather_key", "sunny", "weather")
+        result = db.get_cached_value("weather_key", "weather")
+        assert result == "sunny"
+
+    def test_get_cached_value_miss(self, db):
+        assert db.get_cached_value("nonexistent", "any") is None
+
+    def test_different_keys_stored_independently(self, db):
+        db.cache_value("key_a", "value_a", "weather")
+        db.cache_value("key_b", "value_b", "weather")
+        assert db.get_cached_value("key_a", "weather") == "value_a"
+        assert db.get_cached_value("key_b", "weather") == "value_b"
+
+    def test_cache_json_round_trip(self, db):
+        data = {"temp": 72, "conditions": "clear", "nested": {"wind": 5}}
+        db.cache_json("forecast", data, "weather")
+        result = db.get_cached_json("forecast", "weather")
+        assert result == data
+
+    def test_get_cached_json_invalid_json(self, db):
+        """Manually insert invalid JSON; get_cached_json returns None."""
+        with sqlite3.connect(str(db.db_path)) as conn:
+            conn.execute(
+                "INSERT INTO generic_cache (cache_key, cache_value, cache_type, expires_at) "
+                "VALUES (?, ?, ?, datetime('now', '+24 hours'))",
+                ("bad_json", "not{valid}json", "test"),
+            )
+            conn.commit()
+        assert db.get_cached_json("bad_json", "test") is None
+
+
+class TestCacheCleanup:
+    """Tests for cache expiry cleanup."""
+
+    def test_cleanup_expired_deletes_old(self, db):
+        db.cache_value("old_key", "old_val", "test")
+        # Manually set expires_at to the past
+        with sqlite3.connect(str(db.db_path)) as conn:
+            conn.execute(
+                "UPDATE generic_cache SET expires_at = datetime('now', '-1 hours') "
+                "WHERE cache_key = 'old_key'"
+            )
+            conn.commit()
+        db.cleanup_expired_cache()
+        assert db.get_cached_value("old_key", "test") is None
+
+    def test_cleanup_expired_preserves_valid(self, db):
+        db.cache_value("fresh_key", "fresh_val", "test", cache_hours=720)
+        db.cleanup_expired_cache()
+        assert db.get_cached_value("fresh_key", "test") == "fresh_val"
+
+
+class TestTableManagement:
+    """Tests for table creation whitelist."""
+
+    def test_create_table_allowed(self, db):
+        db.create_table(
+            "greeted_users",
+            "id INTEGER PRIMARY KEY, name TEXT NOT NULL",
+        )
+        with sqlite3.connect(str(db.db_path)) as conn:
+            cursor = conn.execute(
+                "SELECT name FROM sqlite_master WHERE type='table' AND name='greeted_users'"
+            )
+            assert cursor.fetchone() is not None
+
+    def test_create_table_disallowed_raises(self, db):
+        with pytest.raises(ValueError, match="not in allowed tables"):
+            db.create_table("not_allowed", "id INTEGER PRIMARY KEY")
+
+    def test_create_table_sql_injection_name_raises(self, db):
+        with pytest.raises(ValueError):
+            db.create_table("DROP TABLE users; --", "id INTEGER PRIMARY KEY")
+
+
+class TestExecuteQuery:
+    """Tests for raw query execution."""
+
+    def test_execute_query_returns_dicts(self, db):
+        db.set_metadata("test_key", "test_value")
+        rows = db.execute_query("SELECT * FROM bot_metadata WHERE key = ?", ("test_key",))
+        assert len(rows) == 1
+        assert rows[0]["key"] == "test_key"
+        assert rows[0]["value"] == "test_value"
+
+    def test_execute_update_returns_rowcount(self, db):
+        db.set_metadata("del_key", "del_value")
+        count = db.execute_update(
+            "DELETE FROM bot_metadata WHERE key = ?", ("del_key",)
+        )
+        assert count == 1
+
+
+class TestMetadata:
+    """Tests for bot metadata storage."""
+
+    def test_set_and_get_metadata(self, db):
+        db.set_metadata("version", "1.2.3")
+        assert db.get_metadata("version") == "1.2.3"
+
+    def test_get_metadata_miss(self, db):
+        assert db.get_metadata("nonexistent") is None
+
+    def test_bot_start_time_round_trip(self, db):
+        ts = 1234567890.5
+        db.set_bot_start_time(ts)
+        assert db.get_bot_start_time() == ts
+
+
+class TestCacheHoursValidation:
+    """Tests for cache_hours boundary validation."""
+
+    def test_boundary_values(self, db):
+        # Valid boundaries
+        db.cache_value("k1", "v1", "t", cache_hours=1)
+        assert db.get_cached_value("k1", "t") == "v1"
+
+        db.cache_value("k2", "v2", "t", cache_hours=87600)
+        assert db.get_cached_value("k2", "t") == "v2"
+
+        # Invalid boundaries — caught and logged, not stored
+        db.cache_value("k3", "v3", "t", cache_hours=0)
+        db.bot.logger.error.assert_called()
+        assert db.get_cached_value("k3", "t") is None
+
+        db.bot.logger.error.reset_mock()
+        db.cache_value("k4", "v4", "t", cache_hours=87601)
+        db.bot.logger.error.assert_called()
+        assert db.get_cached_value("k4", "t") is None
diff --git a/tests/test_feed_manager_formatting.py b/tests/test_feed_manager_formatting.py
new file mode 100644
index 0000000..a6c4bc2
--- /dev/null
+++ b/tests/test_feed_manager_formatting.py
@@ -0,0 +1,150 @@
+"""Tests for FeedManager pure formatting and filtering logic."""
+
+import json
+from datetime import datetime, timezone, timedelta
+
+import pytest
+from configparser import ConfigParser
+from unittest.mock import Mock
+
+from modules.feed_manager import FeedManager
+
+
+@pytest.fixture
+def fm(mock_logger):
+    """FeedManager with disabled networking for pure-logic tests."""
+    bot = Mock()
+    bot.logger = mock_logger
+    bot.config = ConfigParser()
+    bot.config.add_section("Feed_Manager")
+    bot.config.set("Feed_Manager", "feed_manager_enabled", "false")
+    bot.config.set("Feed_Manager", "max_message_length", "200")
+    bot.db_manager = Mock()
+    bot.db_manager.db_path = "/dev/null"
+    return FeedManager(bot)
+
+
+class TestApplyShortening:
+    """Tests for _apply_shortening()."""
+
+    def test_truncate_short_text_unchanged(self, fm):
+        assert fm._apply_shortening("hello", "truncate:20") == "hello"
+
+    def test_truncate_long_text_adds_ellipsis(self, fm):
+        result = fm._apply_shortening("Hello World", "truncate:5")
+        assert result == "Hello..."
+
+    def test_word_wrap_breaks_at_boundary(self, fm):
+        result = fm._apply_shortening("Hello beautiful world", "word_wrap:15")
+        # word_wrap truncates at a word boundary and appends "..."
+        # "Hello beautiful world"[:15] = "Hello beautiful", last space at 5 (too early),
+        # so result is "Hello beautiful..." (truncated at 15 chars + ellipsis)
+        assert result.endswith("...")
+        # The base text (without ellipsis) should be <= the wrap limit
+        assert len(result.rstrip(".")) <= 15 or result == "Hello beautiful..."
+
+    def test_first_words_limits_count(self, fm):
+        result = fm._apply_shortening("one two three four", "first_words:2")
+        assert result.startswith("one two")
+
+    def test_regex_extracts_group(self, fm):
+        result = fm._apply_shortening("Price: $42.99 today", r"regex:Price: \$(\d+\.\d+)")
+        assert result == "42.99"
+
+    def test_if_regex_returns_then_on_match(self, fm):
+        result = fm._apply_shortening("open", "if_regex:open:YES:NO")
+        assert result == "YES"
+
+    def test_if_regex_returns_else_on_no_match(self, fm):
+        result = fm._apply_shortening("closed", "if_regex:open:YES:NO")
+        assert result == "NO"
+
+    def test_empty_text_returns_empty(self, fm):
+        assert fm._apply_shortening("", "truncate:10") == ""
+
+
+class TestGetNestedValue:
+    """Tests for _get_nested_value()."""
+
+    def test_simple_field_access(self, fm):
+        assert fm._get_nested_value({"name": "test"}, "name") == "test"
+
+    def test_nested_field_access(self, fm):
+        data = {"raw": {"Priority": "high"}}
+        assert fm._get_nested_value(data, "raw.Priority") == "high"
+
+    def test_missing_field_returns_default(self, fm):
+        assert fm._get_nested_value({}, "missing") == ""
+        assert fm._get_nested_value({}, "missing", "N/A") == "N/A"
+
+
+class TestShouldSendItem:
+    """Tests for _should_send_item() filter evaluation."""
+
+    def test_no_filter_sends_all(self, fm):
+        feed = {"id": 1}
+        item = {"raw": {"Priority": "low"}}
+        assert fm._should_send_item(feed, item) is True
+
+    def test_equals_filter_matches(self, fm):
+        feed = {
+            "id": 1,
+            "filter_config": json.dumps({
+                "conditions": [
+                    {"field": "Priority", "operator": "equals", "value": "high"}
+                ]
+            }),
+        }
+        item = {"raw": {"Priority": "high"}}
+        assert fm._should_send_item(feed, item) is True
+
+    def test_equals_filter_rejects(self, fm):
+        feed = {
+            "id": 1,
+            "filter_config": json.dumps({
+                "conditions": [
+                    {"field": "Priority", "operator": "equals", "value": "high"}
+                ]
+            }),
+        }
+        item = {"raw": {"Priority": "low"}}
+        assert fm._should_send_item(feed, item) is False
+
+    def test_in_filter_matches(self, fm):
+        feed = {
+            "id": 1,
+            "filter_config": json.dumps({
+                "conditions": [
+                    {"field": "Priority", "operator": "in", "values": ["high", "highest"]}
+                ]
+            }),
+        }
+        item = {"raw": {"Priority": "highest"}}
+        assert fm._should_send_item(feed, item) is True
+
+    def test_and_logic_all_must_pass(self, fm):
+        feed = {
+            "id": 1,
+            "filter_config": json.dumps({
+                "conditions": [
+                    {"field": "Priority", "operator": "equals", "value": "high"},
+                    {"field": "Status", "operator": "equals", "value": "open"},
+                ],
+                "logic": "AND",
+            }),
+        }
+        # First condition passes, second fails
+        item = {"raw": {"Priority": "high", "Status": "closed"}}
+        assert fm._should_send_item(feed, item) is False
+
+
+class TestFormatTimestamp:
+    """Tests for _format_timestamp()."""
+
+    def test_recent_timestamp(self, fm):
+        five_min_ago = datetime.now(timezone.utc) - timedelta(minutes=5)
+        result = fm._format_timestamp(five_min_ago)
+        assert "5m ago" in result
+
+    def test_none_returns_empty(self, fm):
+        assert fm._format_timestamp(None) == ""
diff --git a/tests/test_plugin_loader.py b/tests/test_plugin_loader.py
new file mode 100644
index 0000000..4c8de4d
--- /dev/null
+++ b/tests/test_plugin_loader.py
@@ -0,0 +1,161 @@
+"""Tests for modules.plugin_loader."""
+
+import pytest
+from unittest.mock import Mock, MagicMock, AsyncMock
+
+from modules.plugin_loader import PluginLoader
+from modules.commands.base_command import BaseCommand
+
+
+@pytest.fixture
+def loader_bot(mock_logger, minimal_config):
+    """Mock bot for PluginLoader tests."""
+    bot = MagicMock()
+    bot.logger = mock_logger
+    bot.config = minimal_config
+    bot.translator = MagicMock()
+    bot.translator.translate = Mock(side_effect=lambda k, **kw: k)
+    bot.translator.get_value = Mock(return_value=None)
+    bot.command_manager = MagicMock()
+    bot.command_manager.monitor_channels = ["general"]
+    bot.command_manager.send_response = AsyncMock(return_value=True)
+    bot.meshcore = None
+    return bot
+
+
+def _load_and_register(loader, plugin_file):
+    """Load a plugin and register it in the loader's internal state (like load_all_plugins does)."""
+    instance = loader.load_plugin(plugin_file)
+    if instance:
+        metadata = instance.get_metadata()
+        name = metadata["name"]
+        loader.loaded_plugins[name] = instance
+        loader.plugin_metadata[name] = metadata
+        loader._build_keyword_mappings(name, metadata)
+    return instance
+
+
+class TestDiscover:
+    """Tests for plugin discovery."""
+
+    def test_discover_plugins_finds_command_files(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        plugins = loader.discover_plugins()
+        assert isinstance(plugins, list)
+        assert len(plugins) > 0
+        # Should find well-known commands
+        assert "ping_command" in plugins
+        assert "help_command" in plugins
+
+    def test_discover_plugins_excludes_base_and_init(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        plugins = loader.discover_plugins()
+        assert "__init__" not in plugins
+        assert "base_command" not in plugins
+
+    def test_discover_alternative_plugins_empty_when_no_dir(self, loader_bot, tmp_path):
+        loader = PluginLoader(loader_bot, commands_dir=str(tmp_path / "nonexistent"))
+        result = loader.discover_alternative_plugins()
+        assert result == []
+
+
+class TestValidatePlugin:
+    """Tests for plugin class validation."""
+
+    def test_validate_missing_execute(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+
+        class NoExecute:
+            name = "test"
+            keywords = ["test"]
+
+        errors = loader._validate_plugin(NoExecute)
+        assert any("execute" in e.lower() for e in errors)
+
+    def test_validate_sync_execute(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+
+        class SyncExecute:
+            name = "test"
+            keywords = ["test"]
+
+            def execute(self, message):
+                return True
+
+        errors = loader._validate_plugin(SyncExecute)
+        assert any("async" in e.lower() for e in errors)
+
+    def test_validate_valid_class(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+
+        class ValidCommand:
+            name = "test"
+            keywords = ["test"]
+
+            async def execute(self, message):
+                return True
+
+        errors = loader._validate_plugin(ValidCommand)
+        assert len(errors) == 0
+
+
+class TestLoadPlugin:
+    """Tests for loading individual plugins."""
+
+    def test_load_ping_command(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        plugin = loader.load_plugin("ping_command")
+        assert plugin is not None
+        assert isinstance(plugin, BaseCommand)
+        assert plugin.name == "ping"
+
+    def test_load_nonexistent_returns_none(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        plugin = loader.load_plugin("totally_nonexistent_command")
+        assert plugin is None
+        assert "totally_nonexistent_command" in loader._failed_plugins
+
+
+class TestKeywordLookup:
+    """Tests for keyword-based plugin lookup after registration."""
+
+    def test_get_plugin_by_keyword(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        _load_and_register(loader, "ping_command")
+        result = loader.get_plugin_by_keyword("ping")
+        assert result is not None
+        assert result.name == "ping"
+
+    def test_get_plugin_by_keyword_miss(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        assert loader.get_plugin_by_keyword("nonexistent") is None
+
+    def test_get_plugin_by_name(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        _load_and_register(loader, "ping_command")
+        result = loader.get_plugin_by_name("ping")
+        assert result is not None
+        assert result.name == "ping"
+
+
+class TestCategoryAndFailed:
+    """Tests for category filtering and failed plugin tracking."""
+
+    def test_get_plugins_by_category(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        _load_and_register(loader, "ping_command")
+        _load_and_register(loader, "help_command")
+        # Ping and help are in the "basic" category
+        result = loader.get_plugins_by_category("basic")
+        assert isinstance(result, dict)
+        assert "ping" in result or "help" in result
+
+    def test_get_failed_plugins_returns_copy(self, loader_bot):
+        loader = PluginLoader(loader_bot)
+        loader.load_plugin("nonexistent_command")
+        failed = loader.get_failed_plugins()
+        assert isinstance(failed, dict)
+        assert "nonexistent_command" in failed
+        # Mutating the return should not affect internal state
+        failed.clear()
+        assert len(loader.get_failed_plugins()) > 0
diff --git a/tests/test_scheduler_logic.py b/tests/test_scheduler_logic.py
new file mode 100644
index 0000000..2fe85de
--- /dev/null
+++ b/tests/test_scheduler_logic.py
@@ -0,0 +1,79 @@
+"""Tests for MessageScheduler pure logic (no threading, no asyncio)."""
+
+import pytest
+from configparser import ConfigParser
+from unittest.mock import Mock
+
+from modules.scheduler import MessageScheduler
+
+
+@pytest.fixture
+def scheduler(mock_logger):
+    """MessageScheduler with mock bot for pure logic tests."""
+    bot = Mock()
+    bot.logger = mock_logger
+    bot.config = ConfigParser()
+    bot.config.add_section("Bot")
+    return MessageScheduler(bot)
+
+
+class TestIsValidTimeFormat:
+    """Tests for _is_valid_time_format()."""
+
+    def test_valid_time_0000(self, scheduler):
+        assert scheduler._is_valid_time_format("0000") is True
+
+    def test_valid_time_2359(self, scheduler):
+        assert scheduler._is_valid_time_format("2359") is True
+
+    def test_valid_time_1200(self, scheduler):
+        assert scheduler._is_valid_time_format("1200") is True
+
+    def test_invalid_time_2400(self, scheduler):
+        assert scheduler._is_valid_time_format("2400") is False
+
+    def test_invalid_time_0060(self, scheduler):
+        assert scheduler._is_valid_time_format("0060") is False
+
+    def test_invalid_time_short(self, scheduler):
+        assert scheduler._is_valid_time_format("123") is False
+
+    def test_invalid_time_letters(self, scheduler):
+        assert scheduler._is_valid_time_format("abcd") is False
+
+    def test_invalid_time_empty(self, scheduler):
+        assert scheduler._is_valid_time_format("") is False
+
+
+class TestGetCurrentTime:
+    """Tests for timezone-aware time retrieval."""
+
+    def test_valid_timezone(self, scheduler):
+        scheduler.bot.config.set("Bot", "timezone", "US/Pacific")
+        result = scheduler.get_current_time()
+        assert result.tzinfo is not None
+
+    def test_invalid_timezone_falls_back(self, scheduler):
+        scheduler.bot.config.set("Bot", "timezone", "Invalid/Zone")
+        result = scheduler.get_current_time()
+        # Should still return a datetime (system time fallback)
+        assert result is not None
+        scheduler.bot.logger.warning.assert_called()
+
+    def test_empty_timezone_uses_system(self, scheduler):
+        scheduler.bot.config.set("Bot", "timezone", "")
+        result = scheduler.get_current_time()
+        assert result is not None
+
+
+class TestHasMeshInfoPlaceholders:
+    """Tests for _has_mesh_info_placeholders()."""
+
+    def test_detects_placeholder(self, scheduler):
+        assert scheduler._has_mesh_info_placeholders("Contacts: {total_contacts}") is True
+
+    def test_no_placeholder_returns_false(self, scheduler):
+        assert scheduler._has_mesh_info_placeholders("Hello world") is False
+
+    def test_detects_legacy_placeholder(self, scheduler):
+        assert scheduler._has_mesh_info_placeholders("Repeaters: {repeaters}") is True