add reverse proxy test

config.yaml

@@ -17,4 +17,4 @@ options:
       Comma-separated list of allowed plugin short names. If empty, any plugin can be installed.
       Plugins installed by the user and their dependencies will be removed automatically if not on
       the list. Included plugins are not automatically installed. 
-    default: "bazaar,blueocean,dependency-check-jenkins-plugin,docker-build-publish,git,kubernetes,ldap,matrix-combinations-parameter,oic-auth,openid,pipeline-groovy-lib,postbuildscript,rebuild,ssh-agent,thinBackup"
+    default: "bazaar,blueocean,dependency-check-jenkins-plugin,docker-build-publish,git,kubernetes,ldap,matrix-combinations-parameter,oic-auth,openid,pipeline-groovy-lib,postbuildscript,rebuild,reverse-proxy-auth-plugin,ssh-agent,thinBackup"

tests/integration/test_plugins.py

@@ -389,6 +389,22 @@ async def test_docker_build_publish_plugin(unit_web_client: UnitWebClient):
     ), f"docker-build-publish configuration option not found. {config_page}"
 
 
+async def test_reverse_proxy_plugin(unit_web_client: UnitWebClient):
+    """
+    arrange: given a Jenkins charm with reverse-proxy-auth-plugin plugin installed.
+    act: when the security configuration is accessed.
+    assert: reverse-proxy-auth-plugin plugin option exists.
+    """
+    await install_plugins(unit_web_client, ("reverse-proxy-auth-plugin",))
+    res = unit_web_client.client.requester.get_url(
+        f"{unit_web_client.web}/manage/configureSecurity"
+    )
+    config_page = str(res.content, "utf-8")
+    assert (
+        "HTTP Header by reverse proxy" in config_page
+    ), f"reverse-proxy-auth-plugin configuration option not found. {config_page}"
+
+
 async def test_dependency_check_plugin(unit_web_client: UnitWebClient):
     """
     arrange: given a Jenkins charm with dependency-check-jenkins-plugin plugin installed.