nixos/memcached: added simple set/get test

The test ensures that the services comes up and accepts/provides values.

nixos/release.nix

@@ -334,6 +334,7 @@ in rec {
   #tests.logstash = callTest tests/logstash.nix {};
   tests.mathics = callTest tests/mathics.nix {};
   tests.matrix-synapse = callTest tests/matrix-synapse.nix {};
+  tests.memcached = callTest tests/memcached.nix {};
   tests.mesos = callTest tests/mesos.nix {};
   tests.misc = callTest tests/misc.nix {};
   tests.mongodb = callTest tests/mongodb.nix {};

nixos/tests/memcached.nix

@@ -0,0 +1,28 @@
+import ./make-test.nix ({ pkgs, ...} : {
+  name = "memcached";
+
+  nodes = {
+    machine =
+      { config, pkgs, ... }:
+      {
+        imports = [ ../modules/profiles/minimal.nix ];
+        services.memcached.enable = true;
+      };
+  };
+
+  testScript = let
+    testScript = pkgs.writeScript "testScript.py" ''
+      #!${pkgs.python3.withPackages (p: [p.memcached])}/bin/python
+
+      import memcache
+      c = memcache.Client(['localhost:11211'])
+      c.set('key', 'value')
+      assert 'value' == c.get('key')
+    '';
+  in ''
+    startAll;
+    $machine->waitForUnit("memcached.service");
+    $machine->waitForOpenPort("11211");
+    $machine->succeed("${testScript}");
+  '';
+})