Use python's assert

Author: davidbrochart

nbclient/tests/test_client.py

@@ -558,14 +558,14 @@ def test_reset_kernel_client(self):
         executor.execute()
         # we didn't ask to reset the kernel client, a new one must have been created
         kc = executor.kc
-        self.assertNotEqual(kc, None)
+        assert kc is not None
         executor.execute()
         # we didn't ask to reset the kernel client, the previously created one must have been reused
-        self.assertEqual(kc, executor.kc)
+        assert kc == executor.kc
         executor.execute(reset_kc=True)
         # we asked to reset the kernel client, the previous one must have been cleaned up,
         # a new one must have been created and also cleaned up
-        self.assertEqual(executor.kc, None)
+        assert executor.kc is None
 
     def test_custom_kernel_manager(self):
         from .fake_kernelmanager import FakeCustomKernelManager