ensure timestamp.txt test

nbgrader/tests/apps/test_nbgrader_submit.py

@@ -248,4 +248,16 @@ def test_submit_max_dir_size(self, exchange, cache, course_dir):
         self._make_file(join("ps1", "large_file"), contents="x" * 2001)
         with pytest.raises(RuntimeError):
             self._submit("ps1", exchange, cache,
-                        flags=['--CourseDirectory.max_dir_size=3'])
+                        flags=['--CourseDirectory.max_dir_size=3'])
+
+    def test_ensure_timestamp(self, exchange, cache, course_dir):
+        # Ensure timestamp is created even if something goes wrong in submitting
+        # If timestamp is not created, feedback workflow can be broken
+        # see: https://github.com/jupyter/nbgrader/pull/1755
+        self._release_and_fetch("ps1", exchange, cache, course_dir)
+        os.chmod("ps1/p1.ipynb", 0o244)
+        with pytest.raises(OSError):
+            self._submit("ps1", exchange, cache)
+        os.chmod("ps1/p1.ipynb", 0o644)
+        dirname = os.listdir(join(exchange, "abc101", "inbound"))[0]
+        assert os.path.isfile(join(exchange, "abc101", "inbound", dirname, "timestamp.txt"))