diff --git a/tests/tests/test_unit/test_cli.py b/tests/tests/test_unit/test_cli.py
index 4d550d9..68189cd 100644
--- a/tests/tests/test_unit/test_cli.py
+++ b/tests/tests/test_unit/test_cli.py
@@ -1,36 +1,51 @@
-from brainreg.core.cli import prep_registration
 from pathlib import Path
+
 import pytest
 
+from brainreg.core.cli import prep_registration
+
+
 def test_prep_registration_different_names(mocker):
     """Check that additional channel names are returned, when unique."""
     args = mocker.Mock()
-    args.brainreg_directory=Path.home()  # This just needs to exist
-    args.additional_images=[Path.home()/"additional_channel_0", Path.home()/"additional_channel_1"]
-    
+    args.brainreg_directory = Path.home()  # This just needs to exist
+    args.additional_images = [
+        Path.home() / "additional_channel_0",
+        Path.home() / "additional_channel_1",
+    ]
+
     _, additional_channel_outputs = prep_registration(args)
     assert "additional_channel_0" in additional_channel_outputs
     assert "additional_channel_1" in additional_channel_outputs
-    
+
 
 def test_additional_channels_same_name_different_parent_name(mocker):
     """
     Check that parent folder name returned if additional channel names are not unique.
     """
     args = mocker.Mock()
-    args.brainreg_directory=Path.home()  # This just needs to exist
-    args.additional_images=[Path.home()/"folder_0/duplicate_name", Path.home()/"folder_1/duplicate_name"]
-    
+    args.brainreg_directory = Path.home()  # This just needs to exist
+    args.additional_images = [
+        Path.home() / "folder_0/duplicate_name",
+        Path.home() / "folder_1/duplicate_name",
+    ]
+
     _, additional_channel_outputs = prep_registration(args)
     assert "folder_1_duplicate_name" in additional_channel_outputs
     assert "folder_1_duplicate_name" in additional_channel_outputs
-    
+
 
 def test_prep_registration_same_name_same_parent_name(mocker):
     """Check that error is thrown if both parent and additional channel name are non-unique."""
     args = mocker.Mock()
-    args.brainreg_directory=Path.home()  # This just needs to exist
-    args.additional_images=[str(Path.home()/"duplicate_name"), str(Path.home()/"duplicate_name")]
-    
-    with pytest.raises(AssertionError, match=".*ensure additional channels have a unique combination of name and parent folder.*"):
-        prep_registration(args)
\ No newline at end of file
+    args.brainreg_directory = Path.home()  # This just needs to exist
+    args.additional_images = [
+        str(Path.home() / "duplicate_name"),
+        str(Path.home() / "duplicate_name"),
+    ]
+
+    with pytest.raises(
+        AssertionError,
+        match=".*ensure additional channels have a unique combination of name and parent folder.*",
+    ):
+        prep_registration(args)