diff --git a/pyproject.toml b/pyproject.toml
index cd3dd07..ed55801 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -74,8 +74,7 @@ zampy="zampy.cli:run_recipe"
 dev = [
   "bump2version",
   "hatch",
-  "ruff",
-  "black",
+  "ruff>0.1.2",  # Ruff with formatter is required
   "mypy",
   "types-requests", # type stubs for request lib
   "types-urllib3", # type stubs for url lib
@@ -100,10 +99,10 @@ features = ["dev"]
 lint = [
   "ruff check src/ tests/",
   "mypy src/",
-  "black --check --diff src/ tests/",
+  "ruff format --check --diff src/ tests/",
 ]
 format = [
-  "black src/ tests/",
+  "ruff format src/ tests/",
   "ruff check src/ tests/ --fix --exit-non-zero-on-fix",
   "lint",
 ]
@@ -127,11 +126,6 @@ ignore_missing_imports = true
 disallow_untyped_defs = true
 python_version = "3.10"
 
-[tool.black]
-line-length = 88
-target-version = ['py310', 'py311']
-include = '\.pyi?$'
-
 [tool.ruff]
 select = [
   "E",  # pycodestyle
diff --git a/src/zampy/datasets/cds_utils.py b/src/zampy/datasets/cds_utils.py
index 0f267b9..4eade9e 100644
--- a/src/zampy/datasets/cds_utils.py
+++ b/src/zampy/datasets/cds_utils.py
@@ -30,6 +30,20 @@
 }
 CONFIG_PATH = Path.home() / ".config" / "zampy" / "zampy_config.yml"
 
+ALL_DAYS = [
+    "01", "02", "03", "04", "05", "06", "07", "08", "09", "10",
+    "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
+    "21", "22", "23", "24", "25", "26", "27", "28", "29", "30",
+    "31", 
+]  # fmt: skip
+
+ALL_HOURS = [  
+    "00:00", "01:00", "02:00", "03:00", "04:00", "05:00", "06:00",
+    "07:00", "08:00", "09:00", "10:00", "11:00", "12:00", "13:00",
+    "14:00", "15:00", "16:00", "17:00", "18:00", "19:00", "20:00",
+    "21:00", "22:00", "23:00",
+]  # fmt: skip
+
 
 def cds_request(
     dataset: str,
@@ -223,20 +237,8 @@ def retrieve_era5(
                 "variable": [cds_var_names[variable]],
                 "year": year,
                 "month": month,
-                # fmt: off
-                "day": [
-                    "01", "02", "03", "04", "05", "06", "07", "08", "09", "10",
-                    "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
-                    "21", "22", "23", "24", "25", "26", "27", "28", "29", "30",
-                    "31",
-                ],
-                "time": [
-                    "00:00", "01:00", "02:00", "03:00", "04:00", "05:00", "06:00",
-                    "07:00", "08:00", "09:00", "10:00", "11:00", "12:00", "13:00",
-                    "14:00", "15:00", "16:00", "17:00", "18:00", "19:00", "20:00",
-                    "21:00", "22:00", "23:00",
-                ],
-                # fmt: on
+                "day": ALL_DAYS,
+                "time": ALL_HOURS,
                 "area": [
                     spatial_bounds.north,
                     spatial_bounds.west,
diff --git a/tests/test_cds_utils.py b/tests/test_cds_utils.py
index c70f805..2fd5e2c 100644
--- a/tests/test_cds_utils.py
+++ b/tests/test_cds_utils.py
@@ -5,6 +5,8 @@
 import numpy as np
 import pytest
 import xarray as xr
+from test_datasets import ALL_DAYS
+from test_datasets import ALL_HOURS
 from test_datasets import data_folder
 from zampy.datasets import cds_utils
 from zampy.datasets.dataset_protocol import SpatialBounds
@@ -54,20 +56,8 @@ def test_cds_request_era5(mock_retrieve, valid_path_config):
                 "variable": ["10m_u_component_of_wind"],
                 "year": "2010",
                 "month": "1",
-                # fmt: off
-                "day": [
-                    "01", "02", "03", "04", "05", "06", "07", "08", "09", "10",
-                    "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
-                    "21", "22", "23", "24", "25", "26", "27", "28", "29", "30",
-                    "31",
-                ],
-                "time": [
-                    "00:00", "01:00", "02:00", "03:00", "04:00", "05:00", "06:00",
-                    "07:00", "08:00", "09:00", "10:00", "11:00", "12:00", "13:00",
-                    "14:00", "15:00", "16:00", "17:00", "18:00", "19:00", "20:00",
-                    "21:00", "22:00", "23:00",
-                ],
-                # fmt: on
+                "day": ALL_DAYS,
+                "time": ALL_HOURS,
                 "area": [
                     spatial_bounds.north,
                     spatial_bounds.west,
diff --git a/tests/test_datasets/__init__.py b/tests/test_datasets/__init__.py
index f000199..ccb1f08 100644
--- a/tests/test_datasets/__init__.py
+++ b/tests/test_datasets/__init__.py
@@ -4,3 +4,18 @@
 
 test_folder = Path(__file__).resolve().parents[1]
 data_folder = test_folder / "test_data"
+
+
+ALL_DAYS = [
+    "01", "02", "03", "04", "05", "06", "07", "08", "09", "10",
+    "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
+    "21", "22", "23", "24", "25", "26", "27", "28", "29", "30",
+    "31", 
+]  # fmt: skip
+
+ALL_HOURS = [  
+    "00:00", "01:00", "02:00", "03:00", "04:00", "05:00", "06:00",
+    "07:00", "08:00", "09:00", "10:00", "11:00", "12:00", "13:00",
+    "14:00", "15:00", "16:00", "17:00", "18:00", "19:00", "20:00",
+    "21:00", "22:00", "23:00",
+]  # fmt: skip
diff --git a/tests/test_datasets/test_era5.py b/tests/test_datasets/test_era5.py
index 3b6cc1c..7e9945e 100644
--- a/tests/test_datasets/test_era5.py
+++ b/tests/test_datasets/test_era5.py
@@ -9,6 +9,8 @@
 from zampy.datasets.catalog import ERA5
 from zampy.datasets.dataset_protocol import SpatialBounds
 from zampy.datasets.dataset_protocol import TimeBounds
+from . import ALL_DAYS
+from . import ALL_HOURS
 from . import data_folder
 
 
@@ -63,18 +65,8 @@ def test_download(self, mock_retrieve, valid_path_config, dummy_dir):
                     "year": "2010",
                     "month": "1",
                     # fmt: off
-                "day": [
-                    "01", "02", "03", "04", "05", "06", "07", "08", "09", "10",
-                    "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
-                    "21", "22", "23", "24", "25", "26", "27", "28", "29", "30",
-                    "31",
-                ],
-                "time": [
-                    "00:00", "01:00", "02:00", "03:00", "04:00", "05:00", "06:00",
-                    "07:00", "08:00", "09:00", "10:00", "11:00", "12:00", "13:00",
-                    "14:00", "15:00", "16:00", "17:00", "18:00", "19:00", "20:00",
-                    "21:00", "22:00", "23:00",
-                ],
+                    "day": ALL_DAYS,
+                    "time": ALL_HOURS,
                     # fmt: on
                     "area": [
                         bbox.north,
diff --git a/tests/test_datasets/test_era5_land.py b/tests/test_datasets/test_era5_land.py
index 8305697..74376c0 100644
--- a/tests/test_datasets/test_era5_land.py
+++ b/tests/test_datasets/test_era5_land.py
@@ -9,6 +9,8 @@
 from zampy.datasets.catalog import ERA5Land
 from zampy.datasets.dataset_protocol import SpatialBounds
 from zampy.datasets.dataset_protocol import TimeBounds
+from . import ALL_DAYS
+from . import ALL_HOURS
 from . import data_folder
 
 
@@ -62,20 +64,8 @@ def test_download(self, mock_retrieve, valid_path_config, dummy_dir):
                     "variable": cds_var_names,
                     "year": "2010",
                     "month": "1",
-                    # fmt: off
-                "day": [
-                    "01", "02", "03", "04", "05", "06", "07", "08", "09", "10",
-                    "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
-                    "21", "22", "23", "24", "25", "26", "27", "28", "29", "30",
-                    "31",
-                ],
-                "time": [
-                    "00:00", "01:00", "02:00", "03:00", "04:00", "05:00", "06:00",
-                    "07:00", "08:00", "09:00", "10:00", "11:00", "12:00", "13:00",
-                    "14:00", "15:00", "16:00", "17:00", "18:00", "19:00", "20:00",
-                    "21:00", "22:00", "23:00",
-                ],
-                    # fmt: on
+                    "day": ALL_DAYS,
+                    "time": ALL_HOURS,
                     "area": [
                         bbox.north,
                         bbox.west,
diff --git a/tests/test_recipes/test_simple_recipe.py b/tests/test_recipes/test_simple_recipe.py
index 3fb7800..536422f 100644
--- a/tests/test_recipes/test_simple_recipe.py
+++ b/tests/test_recipes/test_simple_recipe.py
@@ -17,7 +17,9 @@
 
 
 def test_recipe(tmp_path: Path, mocker):
-    with (patch.object(DATASETS["era5"], "download"),):
+    with (
+        patch.object(DATASETS["era5"], "download"),
+    ):
         mocker.patch(
             "zampy.recipe.config_loader",
             return_value={"working_directory": str(tmp_path.absolute())},