fix: scan the current folder when otag scan gets no path

orvanitag/orvani.py

@@ -567,7 +567,8 @@ class OrvaniTag:
 
     def scan(self, path: str, recursive: bool=False):
 
-        for (root,dirs,files) in os.walk(path, topdown=True):
+        # os.walk('') yields nothing, so an empty path means the current folder
+        for (root,dirs,files) in os.walk(path or '.', topdown=True):
 
             # process every file with a reader plugin
             if self.ENABLE_PLUGINS:

tests/test_plugins.py

@@ -131,3 +131,15 @@ def test_write_uses_config_of_the_files_folder(cwd):
 
     OrvaniTag().add('sub/doc.pdf', '#lofi')
     assert OrvaniTag().write_metadata('sub/doc.pdf', 'pdf') == [6, 'pdf']
+
+
+def test_cmd_scan_defaults_to_current_folder(cwd, monkeypatch):
+    (cwd / 'sub').mkdir()
+    writer = PdfWriter()
+    writer.add_blank_page(72, 72)
+    writer.add_metadata({'/Keywords': '#lofi'})
+    writer.write(cwd / 'sub' / 'doc.pdf')
+
+    monkeypatch.setattr(sys, 'argv', ['otag', 's'])
+    main()
+    assert (cwd / 'sub' / orvani.CONTEXT_FILE).read_text() == 'doc.pdf --- #lofi\n'