diff --git a/tests/service/test_travel_diary_service.py b/tests/service/test_travel_diary_service.py
new file mode 100644
index 0000000..33c8279
--- /dev/null
+++ b/tests/service/test_travel_diary_service.py
@@ -0,0 +1,51 @@
+from unittest.mock import patch
+
+import pytest
+
+from pilgrim import TravelDiary
+from pilgrim.service.travel_diary_service import TravelDiaryService
+
+@patch.object(TravelDiaryService, '_ensure_diary_directory')
+@pytest.mark.asyncio # Marca o teste para rodar código assíncrono
+async def test_create_diary_successfully(mock_ensure_dir, db_session):
+    service = TravelDiaryService(db_session)
+    new_diary = await service.async_create("Viagem para a Serra")
+    assert new_diary is not None
+    assert new_diary.id is not None
+    assert new_diary.name == "Viagem para a Serra"
+    assert new_diary.directory_name == "viagem_para_a_serra"
+
+@patch.object(TravelDiaryService, '_ensure_diary_directory')
+@patch.object(TravelDiaryService, '_sanitize_directory_name', return_value="nome_existente")
+@pytest.mark.asyncio
+async def test_create_diary_handles_integrity_error(mock_sanitize, mock_ensure_dir, db_session):
+    existing_diary = TravelDiary(name="Diário Antigo", directory_name="nome_existente")
+    db_session.add(existing_diary)
+    db_session.commit()
+    service = TravelDiaryService(db_session)
+    with pytest.raises(ValueError, match="Could not create diary"):
+        await service.async_create("Qualquer Nome Novo")
+    mock_ensure_dir.assert_not_called()
+
+def test_sanitize_directory_name_formats_string_correctly(db_session):
+    service = TravelDiaryService(db_session)
+    name1 = "Minha Primeira Viagem"
+    assert service._sanitize_directory_name(name1) == "minha_primeira_viagem"
+    name2 = "Viagem para o #Rio de Janeiro! @2025"
+    assert service._sanitize_directory_name(name2) == "viagem_para_o_rio_de_janeiro_2025"
+    name3 = "  Mochilão na Europa   "
+    assert service._sanitize_directory_name(name3) == "mochilão_na_europa"
+
+def test_sanitize_directory_name_handles_uniqueness(db_session):
+    existing_diary = TravelDiary(name="Viagem para a Praia", directory_name="viagem_para_a_praia")
+    db_session.add(existing_diary)
+    db_session.commit()
+    service = TravelDiaryService(db_session)
+    new_sanitized_name = service._sanitize_directory_name("Viagem para a Praia")
+    assert new_sanitized_name == "viagem_para_a_praia_1"
+    another_diary = TravelDiary(name="Outra Viagem", directory_name="viagem_para_a_praia_1")
+    db_session.add(another_diary)
+    db_session.commit()
+
+    third_sanitized_name = service._sanitize_directory_name("Viagem para a Praia")
+    assert third_sanitized_name == "viagem_para_a_praia_2"
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