diff --git a/tests/test_aprsd_twitter_plugin.py b/tests/test_aprsd_twitter_plugin.py
index 93f4595..eccccd2 100644
--- a/tests/test_aprsd_twitter_plugin.py
+++ b/tests/test_aprsd_twitter_plugin.py
@@ -2,20 +2,293 @@
 
 """Tests for `aprsd_twitter_plugin` package."""
 
+from unittest.mock import MagicMock, patch
+
 import pytest
 
+from aprsd_twitter_plugin.twitter import SendTweetPlugin
+
 
 @pytest.fixture
-def response():
-    """Sample pytest fixture.
-
-    See more at: http://doc.pytest.org/en/latest/fixture.html
-    """
-    # import requests
-    # return requests.get('https://github.com/audreyr/cookiecutter-pypackage')
+def mock_conf():
+    """Create a mock configuration object."""
+    conf = MagicMock()
+    conf.aprsd_twitter_plugin.callsign = "WB4BOR"
+    conf.aprsd_twitter_plugin.apiKey = "test_api_key"
+    conf.aprsd_twitter_plugin.apiKey_secret = "test_api_secret"
+    conf.aprsd_twitter_plugin.access_token = "test_access_token"
+    conf.aprsd_twitter_plugin.access_token_secret = "test_access_secret"
+    conf.aprsd_twitter_plugin.bearer_token = "test_bearer_token"
+    conf.aprsd_twitter_plugin.add_aprs_hashtag = True
+    return conf
 
 
-def test_content(response):
-    """Sample pytest test function with the pytest fixture as an argument."""
-    # from bs4 import BeautifulSoup
-    # assert 'GitHub' in BeautifulSoup(response.content).title.string
+@pytest.fixture
+def plugin(mock_conf):
+    """Create a plugin instance with mocked config."""
+    with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+        plugin_instance = SendTweetPlugin()
+        return plugin_instance
+
+
+@pytest.fixture
+def mock_packet():
+    """Create a mock APRS packet."""
+    packet = MagicMock()
+    packet.from_call = "WB4BOR"
+    packet.message_text = "tw This is a test tweet"
+    return packet
+
+
+class TestSendTweetPlugin:
+    """Test cases for SendTweetPlugin."""
+
+    def test_plugin_initialization(self, mock_conf):
+        """Test that plugin initializes correctly."""
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(SendTweetPlugin, "setup"):
+                plugin = SendTweetPlugin()
+                assert plugin.command_name == "tweet"
+                assert plugin.command_regex == r"^([t][w]\s|twitter)"
+                # enabled should be False before setup() is called
+                assert plugin.enabled is False
+
+    def test_help_method(self, plugin):
+        """Test the help method returns correct help text."""
+        help_text = plugin.help()
+        assert isinstance(help_text, list)
+        assert len(help_text) == 2
+        assert "twitter: Send a Tweet!!" in help_text
+        assert "twitter: Format 'tw <message>'" in help_text
+
+    def test_setup_with_all_config(self, mock_conf):
+        """Test setup method when all configuration is present."""
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            plugin = SendTweetPlugin()
+            plugin.setup()
+            assert plugin.enabled is True
+
+    def test_setup_missing_callsign(self, mock_conf):
+        """Test setup method when callsign is missing."""
+        mock_conf.aprsd_twitter_plugin.callsign = None
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            plugin = SendTweetPlugin()
+            plugin.setup()
+            assert plugin.enabled is False
+
+    def test_setup_missing_api_key(self, mock_conf):
+        """Test setup method when apiKey is missing."""
+        mock_conf.aprsd_twitter_plugin.apiKey = None
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            plugin = SendTweetPlugin()
+            plugin.setup()
+            assert plugin.enabled is False
+
+    def test_setup_missing_api_key_secret(self, mock_conf):
+        """Test setup method when apiKey_secret is missing."""
+        mock_conf.aprsd_twitter_plugin.apiKey_secret = None
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            plugin = SendTweetPlugin()
+            plugin.setup()
+            assert plugin.enabled is False
+
+    def test_setup_missing_access_token(self, mock_conf):
+        """Test setup method when access_token is missing."""
+        mock_conf.aprsd_twitter_plugin.access_token = None
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            plugin = SendTweetPlugin()
+            plugin.setup()
+            assert plugin.enabled is False
+
+    def test_setup_missing_access_token_secret(self, mock_conf):
+        """Test setup method when access_token_secret is missing."""
+        mock_conf.aprsd_twitter_plugin.access_token_secret = None
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            plugin = SendTweetPlugin()
+            plugin.setup()
+            assert plugin.enabled is False
+
+    @patch("aprsd_twitter_plugin.twitter.tweepy.API")
+    @patch("aprsd_twitter_plugin.twitter.tweepy.OAuthHandler")
+    def test_create_client_success(self, mock_oauth, mock_api, plugin, mock_conf):
+        """Test _create_client method when authentication succeeds."""
+        mock_api_instance = MagicMock()
+        mock_api_instance.verify_credentials.return_value = True
+        mock_api.return_value = mock_api_instance
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            client = plugin._create_client()
+
+        assert client is not None
+        mock_api_instance.verify_credentials.assert_called_once()
+
+    @patch("aprsd_twitter_plugin.twitter.tweepy.API")
+    @patch("aprsd_twitter_plugin.twitter.tweepy.OAuthHandler")
+    def test_create_client_auth_failure(self, mock_oauth, mock_api, plugin, mock_conf):
+        """Test _create_client method when authentication fails."""
+        mock_api_instance = MagicMock()
+        mock_api_instance.verify_credentials.side_effect = Exception("Auth failed")
+        mock_api.return_value = mock_api_instance
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            client = plugin._create_client()
+
+        assert client is None
+
+    def test_process_authorized_callsign(self, plugin, mock_packet, mock_conf):
+        """Test process method with authorized callsign."""
+        mock_client = MagicMock()
+        mock_client.update_status = MagicMock()
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=mock_client):
+                result = plugin.process(mock_packet)
+
+        assert result == "Tweet sent!"
+        mock_client.update_status.assert_called_once()
+        # Check that the message was parsed correctly (command removed)
+        call_args = mock_client.update_status.call_args[0][0]
+        assert "This is a test tweet" in call_args
+        # Check that the command prefix "tw " is removed (not just "tw" which appears in "test")
+        assert not call_args.startswith("tw ")
+        assert call_args.startswith("This is a test tweet")
+
+    def test_process_unauthorized_callsign(self, plugin, mock_conf):
+        """Test process method with unauthorized callsign."""
+        packet = MagicMock()
+        packet.from_call = "N0CALL"
+        packet.message_text = "tw This is a test tweet"
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            result = plugin.process(packet)
+
+        assert result == "N0CALL not authorized to tweet!"
+
+    def test_process_callsign_with_suffix(self, plugin, mock_conf):
+        """Test process method with authorized callsign with suffix (e.g., WB4BOR-1)."""
+        packet = MagicMock()
+        packet.from_call = "WB4BOR-1"
+        packet.message_text = "tw This is a test tweet"
+        mock_client = MagicMock()
+        mock_client.update_status = MagicMock()
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=mock_client):
+                result = plugin.process(packet)
+
+        assert result == "Tweet sent!"
+        mock_client.update_status.assert_called_once()
+
+    def test_process_client_creation_failure(self, plugin, mock_packet, mock_conf):
+        """Test process method when client creation fails."""
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=None):
+                result = plugin.process(mock_packet)
+
+        assert result == "Failed to Auth"
+
+    def test_process_message_parsing(self, plugin, mock_conf):
+        """Test that message parsing correctly removes the command."""
+        packet = MagicMock()
+        packet.from_call = "WB4BOR"
+        packet.message_text = "tw Hello world from APRS!"
+        mock_client = MagicMock()
+        mock_client.update_status = MagicMock()
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=mock_client):
+                plugin.process(packet)
+
+        call_args = mock_client.update_status.call_args[0][0]
+        assert (
+            call_args
+            == "Hello world from APRS! #aprs #aprsd #hamradio https://github.com/hemna/aprsd-twitter-plugin"
+        )
+
+    def test_process_with_hashtag_enabled(self, plugin, mock_packet, mock_conf):
+        """Test that hashtags are added when add_aprs_hashtag is enabled."""
+        mock_conf.aprsd_twitter_plugin.add_aprs_hashtag = True
+        mock_client = MagicMock()
+        mock_client.update_status = MagicMock()
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=mock_client):
+                plugin.process(mock_packet)
+
+        call_args = mock_client.update_status.call_args[0][0]
+        assert "#aprs" in call_args
+        assert "#aprsd" in call_args
+        assert "#hamradio" in call_args
+
+    def test_process_with_hashtag_disabled(self, plugin, mock_packet, mock_conf):
+        """Test that hashtags are not added when add_aprs_hashtag is disabled."""
+        mock_conf.aprsd_twitter_plugin.add_aprs_hashtag = False
+        mock_client = MagicMock()
+        mock_client.update_status = MagicMock()
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=mock_client):
+                plugin.process(mock_packet)
+
+        call_args = mock_client.update_status.call_args[0][0]
+        assert "#aprs" not in call_args
+        assert call_args == "This is a test tweet"
+
+    def test_process_twitter_command_variant(self, plugin, mock_conf):
+        """Test process method with 'twitter' command instead of 'tw'."""
+        packet = MagicMock()
+        packet.from_call = "WB4BOR"
+        packet.message_text = "twitter This is another test"
+        mock_client = MagicMock()
+        mock_client.update_status = MagicMock()
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=mock_client):
+                result = plugin.process(packet)
+
+        assert result == "Tweet sent!"
+        call_args = mock_client.update_status.call_args[0][0]
+        assert "This is another test" in call_args
+        # Check that command prefix "twitter " is removed
+        # (not just "twitter" which appears in URL)
+        assert not call_args.startswith("twitter ")
+        assert call_args.startswith("This is another test")
+
+    def test_process_empty_message(self, plugin, mock_conf):
+        """Test process method with empty message after command."""
+        packet = MagicMock()
+        packet.from_call = "WB4BOR"
+        packet.message_text = "tw"
+        mock_client = MagicMock()
+        mock_client.update_status = MagicMock()
+
+        with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+            with patch.object(plugin, "_create_client", return_value=mock_client):
+                plugin.process(packet)
+
+        call_args = mock_client.update_status.call_args[0][0]
+        # Should be empty or just hashtags
+        assert call_args == " #aprs #aprsd #hamradio https://github.com/hemna/aprsd-twitter-plugin"
+
+    def test_create_client_oauth_handler_initialization(self, plugin, mock_conf):
+        """Test that OAuthHandler is initialized with correct credentials."""
+        mock_oauth_instance = MagicMock()
+        mock_oauth_class = MagicMock(return_value=mock_oauth_instance)
+
+        with patch("aprsd_twitter_plugin.twitter.tweepy.OAuthHandler", mock_oauth_class):
+            with patch("aprsd_twitter_plugin.twitter.tweepy.API") as mock_api:
+                mock_api_instance = MagicMock()
+                mock_api_instance.verify_credentials.return_value = True
+                mock_api.return_value = mock_api_instance
+
+                with patch("aprsd_twitter_plugin.twitter.CONF", mock_conf):
+                    plugin._create_client()
+
+        mock_oauth_class.assert_called_once_with(
+            mock_conf.aprsd_twitter_plugin.apiKey,
+            mock_conf.aprsd_twitter_plugin.apiKey_secret,
+        )
+        mock_oauth_instance.set_access_token.assert_called_once_with(
+            mock_conf.aprsd_twitter_plugin.access_token,
+            mock_conf.aprsd_twitter_plugin.access_token_secret,
+        )