rss-bridge: Add simple NixOS test

Add a simple test that starts rss-bridge and tries to fetch the feed of
a demo bridge. On success we know the system setup (web server, PHP) and
rss-bridge are working fine. Internet access is avoided by using a demo
bridge.

nixos/tests/all-tests.nix

@@ -847,6 +847,7 @@ in {
   rshim = handleTest ./rshim.nix {};
   rspamd = handleTest ./rspamd.nix {};
   rspamd-trainer = handleTest ./rspamd-trainer.nix {};
+  rss-bridge = handleTest ./web-apps/rss-bridge.nix {};
   rss2email = handleTest ./rss2email.nix {};
   rstudio-server = handleTest ./rstudio-server.nix {};
   rsyncd = handleTest ./rsyncd.nix {};

nixos/tests/web-apps/rss-bridge.nix

@@ -0,0 +1,22 @@
+{ pkgs, ... }:
+{
+  name = "rss-bridge";
+  meta.maintainers = with pkgs.lib.maintainers; [ mynacol ];
+
+  nodes.machine =
+    { ... }:
+    {
+      services.rss-bridge = {
+        enable = true;
+      };
+    };
+
+  testScript = ''
+    start_all()
+    machine.wait_for_unit("nginx.service")
+    machine.wait_for_unit("phpfpm-rss-bridge.service")
+
+    # check for successful feed download
+    machine.succeed("curl -sS -f 'http://localhost/?action=display&bridge=DemoBridge&context=testCheckbox&format=Atom'")
+  '';
+}

pkgs/servers/web-apps/rss-bridge/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, lib, fetchFromGitHub }:
+{ stdenv, lib, fetchFromGitHub, nixosTests }:
 
 stdenv.mkDerivation rec {
   pname = "rss-bridge";
@@ -20,6 +20,10 @@ stdenv.mkDerivation rec {
     cp -R ./* $out
   '';
 
+  passthru.tests = {
+    basic-functionality = nixosTests.rss-bridge;
+  };
+
   meta = with lib; {
     description = "RSS feed for websites missing it";
     homepage = "https://github.com/RSS-Bridge/rss-bridge";