Apply suggestions from code review

Co-authored-by: Chris Markiewicz <effigies@gmail.com>

Author: jeromedockes

nibabel/loadsave.py

@@ -53,7 +53,7 @@ def _signature_matches_extension(filename):
     try:
         with open(filename, "rb") as fh:
             found_signature = fh.read(len(expected_signature))
-    except Exception:
+    except OSError:
         return False, f"Could not read file: {filename}"
     if found_signature == expected_signature:
         return True, ""

nibabel/tests/test_loadsave.py

@@ -78,14 +78,14 @@ def test_load_empty_image():
 
 @pytest.mark.parametrize("extension", [".gz", ".bz2"])
 def test_load_bad_compressed_extension(tmp_path, extension):
-    file_path = tmp_path.joinpath(f"img.nii{extension}")
+    file_path = tmp_path / f"img.nii{extension}"
     file_path.write_bytes(b"bad")
     with pytest.raises(ImageFileError, match=".*is not a .* file"):
         load(file_path)
 
 
 def test_load_file_that_cannot_be_read(tmp_path):
-    subdir = tmp_path.joinpath("img.nii.gz")
+    subdir = tmp_path / "img.nii.gz"
     subdir.mkdir()
     with pytest.raises(ImageFileError, match="Could not read"):
         load(subdir)