test: Add test case for default app redirect

Co-authored-by: Jonathan Underwood <junderwood@bitcoinbank.co.jp>

test/test_virtual-path/test_forwarding.yml

@@ -0,0 +1,18 @@
+web1:
+  image: web
+  expose:
+    - "81"
+  environment:
+    WEB_PORTS: "81"
+    VIRTUAL_HOST: "www.nginx-proxy.tld"
+    VIRTUAL_PATH: "/web1/"
+    VIRTUAL_DEST: "/"
+
+sut:
+  image: nginxproxy/nginx-proxy:test
+  volumes:
+    - /var/run/docker.sock:/tmp/docker.sock:ro
+    - ../lib/ssl/dhparam.pem:/etc/nginx/dhparam/dhparam.pem:ro
+    - ./certs:/etc/nginx/certs:ro
+  environment:
+    - DEFAULT_ROOT=301 http://$$host/web1$$request_uri