Fix unused variables and imports flagged by codeql scan

docs/conf.py

@@ -12,10 +12,6 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-import sys
-import os
-import shlex
-
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.

jupyter_core/tests/test_application.py

@@ -12,13 +12,13 @@
 
 
 def test_basic():
-    app = JupyterApp()
+    JupyterApp()
 
 
 def test_default_traits():
     app = JupyterApp()
     for trait_name in app.traits():
-        value = getattr(app, trait_name)
+        getattr(app, trait_name)
 
 class DummyApp(JupyterApp):
     name = "dummy-app"

jupyter_core/tests/test_command.py

@@ -87,11 +87,12 @@ def test_subcommand_not_given():
 
 def test_help():
     output = get_jupyter_output('-h')
+    assert '--help' in output
 
 
 def test_subcommand_not_found():
     with pytest.raises(CalledProcessError):
-        output = get_jupyter_output('nonexistant-subcommand')
+        get_jupyter_output('nonexistant-subcommand')
 
 @patch.object(sys, 'argv', [__file__] + sys.argv[1:])
 def test_subcommand_list(tmpdir):

jupyter_core/tests/test_migrate.py

@@ -5,15 +5,13 @@
 import os
 import re
 import shutil
-from subprocess import check_call
 from tempfile import mkdtemp
 from unittest.mock import patch
 
 import pytest
 
 from jupyter_core.utils import ensure_dir_exists
 
-from jupyter_core.paths import jupyter_data_dir
 from jupyter_core.migrate import (
     migrate, migrate_one, migrate_config,
     migrate_dir, migrate_file, migrate_static_custom,