Factorize content checking

test/test_content/test_content.py

@@ -76,22 +76,22 @@ class FileTest(unittest.TestCase, metaclass=dynamic.DynamicTest):
     @classmethod
     def _clean_path(cls, elem):
         """Shorten the path relative to the `songs` directory"""
-        if isinstance(elem, song.SongRenderer):
-            songpath = os.path.join(os.path.dirname(__file__), 'datadir', 'songs')
-            return files.path2posix(files.relpath(elem.song.fullpath, songpath))
 
-        elif isinstance(elem, section.Section):
+        latex_command_classes = (
+            section.Section,
+            songsection.SongSection,
+            setcounter.CounterSetter,
+            )
+        if isinstance(elem, latex_command_classes):
             return elem.render(None)[1:]
 
-        elif isinstance(elem, songsection.SongSection):
+        elif isinstance(elem, song.SongRenderer):
-            return elem.render(None)[1:]
+            songpath = os.path.join(os.path.dirname(__file__), 'datadir', 'songs')
+            return files.path2posix(files.relpath(elem.song.fullpath, songpath))
 
         elif isinstance(elem, tex.LaTeX):
             return files.path2posix(elem.filename)
 
-        elif isinstance(elem, setcounter.CounterSetter):
-            return elem.render(None)[1:]
-
         else:
             raise Exception(elem)