diff --git a/tests/storage/test_filesystem.py b/tests/storage/test_filesystem.py
index 94e5d17..20bbf3a 100644
--- a/tests/storage/test_filesystem.py
+++ b/tests/storage/test_filesystem.py
@@ -44,6 +44,25 @@ class TestFilesystemStorage(StorageTests):
         (item_file,) = tmpdir.listdir()
         assert "/" not in item_file.basename and item_file.isfile()
 
+    def test_ignore_tmp_files(self, tmpdir):
+        """Test that files with .tmp suffix beside .ics files are ignored."""
+        s = self.storage_class(str(tmpdir), '.ics')
+        s.upload(Item('UID:xyzxyz'))
+        item_file, = tmpdir.listdir()
+        item_file.copy(item_file.new(ext='tmp'))
+        assert len(tmpdir.listdir()) == 2
+        assert len(list(s.list())) == 1
+
+    def test_ignore_tmp_files_empty_fileext(self, tmpdir):
+        """Test that files with .tmp suffix are ignored with empty fileext."""
+        s = self.storage_class(str(tmpdir), '')
+        s.upload(Item('UID:xyzxyz'))
+        item_file, = tmpdir.listdir()
+        item_file.copy(item_file.new(ext='tmp'))
+        assert len(tmpdir.listdir()) == 2
+        # assert False, tmpdir.listdir() # enable to see the created filename
+        assert len(list(s.list())) == 1
+
     def test_too_long_uid(self, tmpdir):
         s = self.storage_class(str(tmpdir), ".txt")
         item = Item("UID:" + "hue" * 600)