Do not dynamically add dag_doc.md when parsing the test (#59933)

* Do not dynamically add dag_doc.md when parsing the test

The file should not be dynamically generated, as it is expected,
it should be just added to the repo.

* Apply suggestion from @potiuk

Author: potiuk

providers/openlineage/tests/system/openlineage/dag_doc.md

@@ -0,0 +1,19 @@
+<!--
+ 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.
+ -->
+# MD doc file

providers/openlineage/tests/system/openlineage/example_openlineage_docs_file_dag.py

@@ -23,7 +23,6 @@
 
 from __future__ import annotations
 
-import os
 from datetime import datetime
 
 from airflow import DAG
@@ -32,20 +31,14 @@
 from system.openlineage.expected_events import get_expected_event_file_path
 from system.openlineage.operator import OpenLineageTestOperator
 
-# Create file at DAG parsing to make sure it's in the right place
-_FILE_PATH = "dag_doc.md"
-if not os.path.exists(_FILE_PATH):
-    with open(_FILE_PATH, "w") as f:
-        f.write("# MD doc file")
-
 DAG_ID = "openlineage_docs_file_dag"
 
 with DAG(
     dag_id=DAG_ID,
     start_date=datetime(2021, 1, 1),
     schedule=None,
     catchup=False,
-    doc_md=_FILE_PATH,
+    doc_md="dag_doc.md",
     default_args={"retries": 0},
 ) as dag:
     do_nothing_task = BashOperator(task_id="do_nothing_task", bash_command="sleep 1;")