tests: cleanup test code

- remove unused imports in test cases
- fix code smells and code style in conftest.py

test/test_logs/test_log_disabled.py

@@ -1,5 +1,3 @@
-import pytest
-
 def test_log_disabled(docker_compose, nginxproxy):
     r = nginxproxy.get("http://nginx-proxy.test/port")
     assert r.status_code == 200

test/test_logs/test_log_format.py

@@ -1,5 +1,3 @@
-import pytest
-
 def test_log_format(docker_compose, nginxproxy):
     r = nginxproxy.get("http://nginx-proxy.test/port")
     assert r.status_code == 200

test/test_logs/test_log_json.py

@@ -1,5 +1,3 @@
-import pytest
-
 def test_log_json(docker_compose, nginxproxy):
     log_conf = [line for line in nginxproxy.get_conf().decode('ASCII').splitlines() if "log_format vhost escape=" in line]
     assert "{\"time_local\":\"$time_iso8601\"," in log_conf[0]

test/test_logs/test_log_json_format.py

@@ -1,5 +1,3 @@
-import pytest
-
 def test_log_json_format(docker_compose, nginxproxy):
     log_conf = [line for line in nginxproxy.get_conf().decode('ASCII').splitlines() if "log_format vhost escape=" in line]
     assert "{\"time_local\":\"$time_iso8601\"," in log_conf[0]