Shared Catalog

tests/test_catalogue.py

@@ -62,3 +62,20 @@ class CatalogueTests(unittest.TestCase):
       with self.assertRaisesRegex(ValueError, 'output path collides'):
         generate_practice_scores(source, output)
       self.assertFalse(output.exists())
+  def test_runtime_id_collisions_preserve_existing_output(self):
+    with tempfile.TemporaryDirectory() as temporary:
+      source, output = Path(temporary) / 'source', Path(temporary) / 'output'
+      names = ('chord/one-two/three.xml', 'chord/one/two-three.xml')
+      for name in names:
+        path = source / name
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text(xml_score(xml_note()), encoding='utf-8')
+      output.mkdir()
+      sentinel = output / 'existing.json'
+      sentinel.write_text('unchanged', encoding='utf-8')
+      with self.assertRaisesRegex(ValueError, 'practice exercise ID collision') as error:
+        generate_practice_scores(source, output)
+      for name in names:
+        self.assertIn(name, str(error.exception))
+      self.assertEqual(list(output.iterdir()), [sentinel])
+      self.assertEqual(sentinel.read_text(), 'unchanged')