one more to fix

tests/test_b2shareoperator.py

 import unittest
 from airflow.utils.state import State
+from airflow.utils.dates import days_ago
 from dags.b2shareoperator import B2ShareOperator
 from airflow import DAG
 from airflow.models.taskinstance import TaskInstance
@@ -9,13 +10,13 @@ TEST_DAG_ID = 'test_my_custom_operator'
 
 class B2ShareOperatorTest(unittest.TestCase):
    def setUp(self):
-       self.dag = DAG(TEST_DAG_ID, schedule_interval='@daily', default_args={'start_date' : DEFAULT_DATE})
+       self.dag = DAG(TEST_DAG_ID, schedule_interval='@daily', default_args={'start_date' : days_ago(2)})
        self.op = B2ShareOperator(
            dag=self.dag,
            task_id='test',
            name='test_name'
        )
-       self.ti = TaskInstance(task=self.op, execution_date=DEFAULT_DATE)
+       self.ti = TaskInstance(task=self.op, execution_date=days_ago(1))
 
    def test_execute_no_trigger(self):
        self.ti.run(ignore_ti_state=True)