test: use `not` instead of `is False` in assert (#366)

* test: use == instead of is when comparing equality

* use not instead of ==
diff --git a/tests/unit/test_extended_operation.py b/tests/unit/test_extended_operation.py
index ad62b77..c551bfa 100644
--- a/tests/unit/test_extended_operation.py
+++ b/tests/unit/test_extended_operation.py
@@ -70,8 +70,8 @@
 def test_constructor():
     ex_op, refresh, _ = make_extended_operation()
     assert ex_op._extended_operation == refresh.responses[0]
-    assert ex_op.cancelled() is False
-    assert ex_op.done() is False
+    assert not ex_op.cancelled()
+    assert not ex_op.done()
     assert ex_op.name == TEST_OPERATION_NAME
     assert ex_op.status == CustomOperation.StatusCode.PENDING
     assert ex_op.error_code is None