tests: Add tests for how Let's Encrypt ACME challenge is handled

At the moment no changes to functionality are done, only the current
behavior is captured.

test/test_ssl/wildcard_cert_and_nohttps/acme_root/.well-known/acme-challenge/test-filename

@@ -0,0 +1 @@
+challenge-teststring

test/test_ssl/wildcard_cert_and_nohttps/docker-compose.yml

@@ -7,6 +7,7 @@ services:
     volumes:
       - /var/run/docker.sock:/tmp/docker.sock:ro
       - ./certs:/etc/nginx/certs:ro
+      - ./acme_root:/usr/share/nginx/html:ro
 
   web1:
     image: web

test/test_ssl/wildcard_cert_and_nohttps/test_wildcard_cert_nohttps.py

@@ -1,5 +1,6 @@
 import pytest
 from ssl import CertificateError
+from requests import ConnectionError
 from requests.exceptions import SSLError
 
 
@@ -32,3 +33,25 @@ def test_https_request_to_nohttps_vhost_goes_to_fallback_server(docker_compose,
 
     r = nginxproxy.get("https://3.web.nginx-proxy.tld/port", verify=False)
     assert r.status_code == 503
+
+
+@pytest.mark.parametrize("subdomain,acme_should_work", [
+    (1, True),
+    (2, True),
+    (3, False),
+])
+def test_acme_challenge_works(
+    docker_compose, nginxproxy, acme_challenge_path, subdomain, acme_should_work
+):
+    if acme_should_work:
+        r = nginxproxy.get(
+            f"https://{subdomain}.web.nginx-proxy.tld/{acme_challenge_path}",
+            allow_redirects=False
+        )
+        assert r.status_code == 404
+    else:
+        with pytest.raises(ConnectionError):
+            nginxproxy.get(
+                f"https://{subdomain}.web.nginx-proxy.tld/{acme_challenge_path}",
+                allow_redirects=False
+            )