nixos/tests: add snapcast

Checks
- if all configured ports are listened on
- if all pipes for multiple streams get set up
- if rpc interaction is possible

nixos/tests/snapcast.nix

@@ -0,0 +1,58 @@
+import ./make-test-python.nix ({ pkgs, ...} :
+
+let
+  port = 10004;
+  tcpPort = 10005;
+  httpPort = 10080;
+in {
+  name = "snapcast";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ hexa ];
+  };
+
+  nodes = {
+    server = {
+      services.snapserver = {
+        enable = true;
+        port = port;
+        tcp.port = tcpPort;
+        http.port = httpPort;
+        streams = {
+          mpd = {
+            type = "pipe";
+            location = "/run/snapserver/mpd";
+          };
+          bluetooth = {
+            type = "pipe";
+            location = "/run/snapserver/bluetooth";
+          };
+        };
+      };
+    };
+  };
+
+  testScript = ''
+    import json
+
+    get_rpc_version = {"id": "1", "jsonrpc": "2.0", "method": "Server.GetRPCVersion"}
+
+    start_all()
+
+    server.wait_for_unit("snapserver.service")
+    server.wait_until_succeeds("ss -ntl | grep -q ${toString port}")
+    server.wait_until_succeeds("ss -ntl | grep -q ${toString tcpPort}")
+    server.wait_until_succeeds("ss -ntl | grep -q ${toString httpPort}")
+
+    with subtest("check that pipes are created"):
+        server.succeed("test -p /run/snapserver/mpd")
+        server.succeed("test -p /run/snapserver/bluetooth")
+
+    with subtest("test tcp json-rpc"):
+        server.succeed(f"echo '{json.dumps(get_rpc_version)}' | nc -w 1 localhost ${toString tcpPort}")
+
+    with subtest("test http json-rpc"):
+        server.succeed(
+            "curl --fail http://localhost:${toString httpPort}/jsonrpc -d '{json.dumps(get_rpc_version)}'"
+        )
+  '';
+})