diff --git a/app/test/__init__.py b/app/test/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/app/test/test_usecases.py b/app/test/test_usecases.py
new file mode 100644
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--- /dev/null
+++ b/app/test/test_usecases.py
@@ -0,0 +1,103 @@
+from unittest.mock import Mock, MagicMock, patch
+import pytest
+from app.domain import ports
+from app.services import usecases
+from app.services.usecases import NoChatFound, InputNotProvided
+
+
+@pytest.fixture
+def mock_agent():
+    return Mock(spec=ports.AgentPort)
+
+@pytest.fixture
+def mock_db():
+    return Mock(spec=ports.ChatRepository)
+
+@pytest.fixture
+def mock_transcriber():
+    return Mock(spec=ports.TranscriptionPort)
+
+@pytest.fixture
+def chat_service(mock_agent, mock_db, mock_transcriber):
+    return usecases.ChatService(mock_agent, mock_db, mock_transcriber)
+
+def test_should_start_conversation_when_start_conversation_is_called(chat_service, mock_db):
+    # Arrange
+    with patch('app.domain.models.Chat', return_value=MagicMock(id="456")) as mock_chat:
+
+        # Act
+        result = chat_service.start_conversation()
+
+        # Assert
+        mock_db.save_chat.assert_called_once_with(mock_chat.return_value)
+        assert result == "456"
+
+def test_should_raise_exception_when_continue_conversation_is_called_with_invalid_conversation_id(chat_service, mock_db):
+    # Arrange
+    conversation_id = "789"
+    query = "Hello World"
+    mock_db.get_chat.return_value = None
+
+    # Act
+    with pytest.raises(NoChatFound) as exc:
+        chat_service.continue_conversation(conversation_id, query=query)
+
+    # Assert
+    assert str(exc.value) == "Chat not found"
+
+def test_should_raise_exception_when_continue_conversation_is_called_with_no_input(chat_service, mock_db):
+    # Arrange
+    conversation_id = "456"
+    query = None
+
+    # Act & Assert
+    with pytest.raises(InputNotProvided) as exc:
+        chat_service.continue_conversation(conversation_id, query=query)
+
+    # Assert
+    assert str(exc.value) == "No input provided"
+
+def test_should_continue_conversation_when_continue_conversation_is_called(chat_service, mock_db, mock_agent):
+    # Arrange
+    with patch('app.domain.models.Chat', return_value=MagicMock()) as mock_chat:
+
+        conversation_id = "456"
+        query = "How are you?"
+        mock_chat.return_value.get_conversation_history.return_value = []
+        mock_db.get_chat.return_value = mock_chat.return_value
+        mock_agent.get_last_response.return_value = "Hello, how are you?"
+
+        # Act
+        result = chat_service.continue_conversation(conversation_id, query)
+
+        # Assert
+        mock_db.get_chat.assert_called_once_with(conversation_id)
+        mock_agent.set_memory_variables.assert_called_once_with([])
+        mock_agent.get_last_response.assert_called_once()
+        mock_agent.get_conversation_history.assert_called_once()
+        mock_db.save_chat.assert_called_once()
+
+        assert result == "Hello, how are you?"
+
+def test_should_continue_conversation_when_continue_conversation_is_called_with_voice_file(chat_service, mock_db, mock_agent, mock_transcriber):
+    # Arrange
+    with patch('app.domain.models.Chat', return_value=MagicMock()) as mock_chat:
+
+        conversation_id = "456"
+        voice_file = b"audio_file"
+
+        mock_chat.return_value.get_conversation_history.return_value = []
+        mock_db.get_chat.return_value = mock_chat.return_value
+        mock_agent.get_last_response.return_value = "Voice response"
+        mock_transcriber.transcribe_audio.return_value = "Transcribed message"
+
+        # Act
+        result = chat_service.continue_conversation(conversation_id, voice_file=voice_file)
+
+        # Assert
+        mock_db.get_chat.assert_called_once_with(conversation_id)
+        mock_transcriber.transcribe_audio.assert_called_once_with(voice_file)
+        mock_agent.set_memory_variables.assert_called_once_with([])
+        mock_agent.get_last_response.assert_called_once()
+        mock_agent.get_conversation_history.assert_called_once()
+        mock_db.save_chat.assert_called_once_with(mock_chat.return_value)