Add fixture for saving exiting config file

e2e/test_sample.py

@@ -1,22 +1,46 @@
+import os
+import subprocess
+import sys
+import pytest
+
+
+@pytest.fixture()
+def secure_config_file():
+    home_directory = os.path.expanduser("~")
+    config_file_name = os.path.join(home_directory, ".podcast_downloader_config.json")
+    backup_config_file_name = os.path.join(home_directory, ".safe_copy_podcast_downloader_config.json")
+
+    if os.path.exists(config_file_name):
+        os.rename(config_file_name, backup_config_file_name)
+
+    yield config_file_name
+
+    if os.path.exists(backup_config_file_name):
+        os.remove(config_file_name)
+        os.rename(backup_config_file_name, config_file_name)
+
+
 def build_server():
     pass
 
 
-def build_config():
-    pass
+def build_config(config_path):
+    with open(config_path, 'w') as file:
+        file.write('''{
+        }''')
 
 
 def run_podcast_downloader():
-    pass
+    subprocess.check_call([sys.executable, "-m", "podcast_downloader"])
 
 
 def check_the_download_directory():
     pass
 
 
-def test_answer():
+def test_answer(secure_config_file):
     build_server()
-    build_config()
+    build_config(secure_config_file)
 
     run_podcast_downloader()