Remove singularity test DAG: not working yet

dags/singularity_test.py

- 
-#
-# Licensed to the Apache Software Foundation (ASF) under one
-# or more contributor license agreements.  See the NOTICE file
-# distributed with this work for additional information
-# regarding copyright ownership.  The ASF licenses this file
-# to you under the Apache License, Version 2.0 (the
-# "License"); you may not use this file except in compliance
-# with the License.  You may obtain a copy of the License at
-#
-#   http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing,
-# software distributed under the License is distributed on an
-# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-# KIND, either express or implied.  See the License for the
-# specific language governing permissions and limitations
-# under the License.
-
-from datetime import datetime, timedelta
-
-from airflow import DAG
-from airflow.operators.bash import BashOperator
-from airflow.providers.singularity.operators.singularity import SingularityOperator
-
-with DAG(
-    'singularity_sample',
-    default_args={'retries': 1},
-    schedule_interval=timedelta(minutes=10),
-    start_date=datetime(2021, 1, 1),
-    catchup=False,
-) as dag:
-
-    t1 = BashOperator(task_id='print_date', bash_command='date')
-
-    t2 = BashOperator(task_id='sleep', bash_command='sleep 5', retries=3)
-
-    t3 = SingularityOperator(
-        command='/bin/sleep 30',
-        image='docker://busybox:1.30.1',
-        task_id='singularity_op_tester',
-    )
-
-    t4 = BashOperator(task_id='print_hello', bash_command='echo "hello world!!!"')
-
-    t1 >> [t2, t3]
-    t3 >> t4