tests: factor out base nginx-proxy config

test/test_keepalive/test_keepalive.yml

@@ -1,4 +1,8 @@
 services:
+  nginx-proxy:
+    environment:
+      HTTPS_METHOD: nohttps
+
   keepalive-disabled:
     image: web
     expose:
@@ -18,7 +22,7 @@ services:
       VIRTUAL_HOST: keepalive-enabled.nginx-proxy.test
     labels:
       com.github.nginx-proxy.nginx-proxy.keepalive: "64"
-  
+
   keepalive-auto:
     image: web
     deploy:
@@ -30,9 +34,3 @@ services:
       WEB_PORTS: "80"
       VIRTUAL_HOST: keepalive-auto.nginx-proxy.test
 
-  sut:
-    image: nginxproxy/nginx-proxy:test
-    volumes:
-      - /var/run/docker.sock:/tmp/docker.sock:ro
-    environment:
-      HTTPS_METHOD: nohttps