diff --git a/tests/import_project_test.py b/tests/import_project_test.py
index 2dea06f..685d2cf 100644
--- a/tests/import_project_test.py
+++ b/tests/import_project_test.py
@@ -1,7 +1,7 @@
 import corrlib.toml as t
 
 
-def test_toml_check_measurement_data():
+def test_toml_check_measurement_data() -> None:
     measurements = {
                     "a":
                         {
diff --git a/tests/sfcf_in_test.py b/tests/sfcf_in_test.py
index 72921e7..5e4ff83 100644
--- a/tests/sfcf_in_test.py
+++ b/tests/sfcf_in_test.py
@@ -1,7 +1,7 @@
 import corrlib.input.sfcf as input
 import json
 
-def test_get_specs():
+def test_get_specs() -> None:
     parameters = {
         'crr': [
             'f_P', 'f_A'
diff --git a/tests/test_initialization.py b/tests/test_initialization.py
index 1ea0ece..9284c82 100644
--- a/tests/test_initialization.py
+++ b/tests/test_initialization.py
@@ -1,22 +1,23 @@
 import corrlib.initialization as init
 import os
 import sqlite3 as sql
+from pathlib import Path
 
-def test_init_folders(tmp_path):
+def test_init_folders(tmp_path: Path) -> None:
     dataset_path = tmp_path / "test_dataset"
     init.create(str(dataset_path))
     assert os.path.exists(str(dataset_path))
     assert os.path.exists(str(dataset_path / "backlogger.db"))
 
 
-def test_init_folders_no_tracker(tmp_path):
+def test_init_folders_no_tracker(tmp_path: Path) -> None:
     dataset_path = tmp_path / "test_dataset"
     init.create(str(dataset_path), tracker="None")
     assert os.path.exists(str(dataset_path))
     assert os.path.exists(str(dataset_path / "backlogger.db"))
 
 
-def test_init_config(tmp_path):
+def test_init_config(tmp_path: Path) -> None:
     dataset_path = tmp_path / "test_dataset"
     init.create(str(dataset_path), tracker="None")
     config_path = dataset_path / ".corrlib"
@@ -34,7 +35,7 @@ def test_init_config(tmp_path):
     assert config.get("paths", "import_scripts_path") == "import_scripts"
 
 
-def test_init_db(tmp_path):
+def test_init_db(tmp_path: Path) -> None:
     dataset_path = tmp_path / "test_dataset"
     init.create(str(dataset_path))
     assert os.path.exists(str(dataset_path / "backlogger.db"))
diff --git a/tests/tools_test.py b/tests/tools_test.py
index 60a5a4a..0399be0 100644
--- a/tests/tools_test.py
+++ b/tests/tools_test.py
@@ -1,6 +1,7 @@
 from corrlib import tools as tl
 from configparser import ConfigParser
 import os
+from pathlib import Path
 
 
 def test_m2k() -> None:
@@ -31,7 +32,7 @@ def test_list2str() -> None:
     assert tl.list2str(["1", "2", "3"]) == "1,2,3"
 
 
-def test_set_config(tmp_path: str) -> None:
+def test_set_config(tmp_path: Path) -> None:
     section = "core"
     option = "test_option"
     value = "test_value"
@@ -61,7 +62,7 @@ def test_set_config(tmp_path: str) -> None:
     assert config.get('core', 'test_option2', fallback="not the value") == "test_value3"
 
 
-def test_get_db_file(tmp_path: str) -> None:
+def test_get_db_file(tmp_path: Path) -> None:
     section = "paths"
     option = "db"
     value = "test_value"
@@ -70,7 +71,7 @@ def test_get_db_file(tmp_path: str) -> None:
     assert tl.get_db_file(tmp_path) == "test_value"
 
 
-def test_cache_enabled(tmp_path: str) -> None:
+def test_cache_enabled(tmp_path: Path) -> None:
     section = "core"
     option = "cached"
     value = "True"