diff --git a/tests/conftest.py b/tests/conftest.py
index 1ae9878..a74ba4c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,5 +1,5 @@
-import os
 from typing import AsyncGenerator
+from unittest.mock import MagicMock
 
 import pytest
 
@@ -7,6 +7,7 @@ from alembic import command, config
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from database.engine import engine
+from didier import Didier
 
 
 @pytest.fixture(scope="session")
@@ -38,3 +39,16 @@ async def database_session(tables) -> AsyncGenerator[AsyncSession, None]:
         await transaction.rollback()
 
     await connection.close()
+
+
+@pytest.fixture
+def mock_client() -> Didier:
+    """Fixture to get a mock Didier instance
+    The mock uses 0 as the id
+    """
+    mock_client = MagicMock()
+    mock_user = MagicMock()
+    mock_user.id = 0
+    mock_client.user = mock_user
+
+    return mock_client
diff --git a/tests/test_didier/__init__.py b/tests/test_didier/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_didier/test_utils/__init__.py b/tests/test_didier/test_utils/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_didier/test_utils/test_discord/__init__.py b/tests/test_didier/test_utils/test_discord/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_didier/test_utils/test_discord/test_prefix.py b/tests/test_didier/test_utils/test_discord/test_prefix.py
new file mode 100644
index 0000000..d49e8e3
--- /dev/null
+++ b/tests/test_didier/test_utils/test_discord/test_prefix.py
@@ -0,0 +1,84 @@
+from unittest.mock import MagicMock
+
+from didier import Didier
+from didier.utils.discord.prefix import get_prefix
+
+
+def test_get_prefix_didier(mock_client: Didier):
+    """Test the "didier" prefix"""
+    mock_message = MagicMock()
+    mock_message.content = "didier test"
+    assert get_prefix(mock_client, mock_message) == "didier "
+
+
+def test_get_prefix_didier_cased(mock_client: Didier):
+    """Test the "didier" prefix with random casing"""
+    mock_message = MagicMock()
+    mock_message.content = "Didier test"
+    assert get_prefix(mock_client, mock_message) == "Didier "
+
+    mock_message = MagicMock()
+    mock_message.content = "DIDIER test"
+    assert get_prefix(mock_client, mock_message) == "DIDIER "
+
+    mock_message = MagicMock()
+    mock_message.content = "DiDiEr test"
+    assert get_prefix(mock_client, mock_message) == "DiDiEr "
+
+
+def test_get_prefix_default(mock_client: Didier):
+    """Test the fallback prefix (used when nothing matched)"""
+    mock_message = MagicMock()
+    mock_message.content = "random message"
+    assert get_prefix(mock_client, mock_message) == "didier"
+
+
+def test_get_prefix_big_d(mock_client: Didier):
+    """Test the "big d" prefix"""
+    mock_message = MagicMock()
+    mock_message.content = "big d test"
+    assert get_prefix(mock_client, mock_message) == "big d "
+
+
+def test_get_prefix_big_d_cased(mock_client: Didier):
+    """Test the "big d" prefix with random casing"""
+    mock_message = MagicMock()
+    mock_message.content = "Big d test"
+    assert get_prefix(mock_client, mock_message) == "Big d "
+
+    mock_message = MagicMock()
+    mock_message.content = "Big D test"
+    assert get_prefix(mock_client, mock_message) == "Big D "
+
+    mock_message = MagicMock()
+    mock_message.content = "BIG D test"
+    assert get_prefix(mock_client, mock_message) == "BIG D "
+
+
+def test_get_prefix_mention_username(mock_client: Didier):
+    """Test the @mention prefix when mentioned by username"""
+    mock_message = MagicMock()
+    prefix = f"<@{mock_client.user.id}> "
+    mock_message.content = f"{prefix}test"
+
+    assert get_prefix(mock_client, mock_message) == prefix
+
+
+def test_get_prefix_mention_nickname(mock_client: Didier):
+    """Test the @mention prefix when mentioned by server nickname"""
+    mock_message = MagicMock()
+    prefix = f"<@!{mock_client.user.id}> "
+    mock_message.content = f"{prefix}test"
+
+    assert get_prefix(mock_client, mock_message) == prefix
+
+
+def test_get_prefix_whitespace(mock_client: Didier):
+    """Test that variable whitespace doesn't matter"""
+    mock_message = MagicMock()
+    mock_message.content = "didiertest"
+    assert get_prefix(mock_client, mock_message) == "didier"
+
+    mock_message = MagicMock()
+    mock_message.content = "didier  test"
+    assert get_prefix(mock_client, mock_message) == "didier  "
diff --git a/tests/test_dummy.py b/tests/test_dummy.py
deleted file mode 100644
index 569bcda..0000000
--- a/tests/test_dummy.py
+++ /dev/null
@@ -1,2 +0,0 @@
-def test_dummy(tables):
-    assert True