nixos/stalwart-mail: add vm test

nixos/tests/all-tests.nix

@@ -728,6 +728,7 @@ in {
   sslh = handleTest ./sslh.nix {};
   sssd = handleTestOn ["x86_64-linux"] ./sssd.nix {};
   sssd-ldap = handleTestOn ["x86_64-linux"] ./sssd-ldap.nix {};
+  stalwart-mail = handleTest ./stalwart-mail.nix {};
   stargazer = runTest ./web-servers/stargazer.nix;
   starship = handleTest ./starship.nix {};
   static-web-server = handleTest ./web-servers/static-web-server.nix {};

nixos/tests/stalwart-mail.nix

@@ -0,0 +1,117 @@
+# Rudimentary test checking that the Stalwart email server can:
+# - receive some message through SMTP submission, then
+# - serve this message through IMAP.
+
+let
+  certs = import ./common/acme/server/snakeoil-certs.nix;
+  domain = certs.domain;
+
+in import ./make-test-python.nix ({ lib, ... }: {
+  name = "stalwart-mail";
+
+  nodes.main = { pkgs, ... }: {
+    security.pki.certificateFiles = [ certs.ca.cert ];
+
+    services.stalwart-mail = {
+      enable = true;
+      settings = {
+        server.hostname = domain;
+
+        certificate."snakeoil" = {
+          cert = "file://${certs.${domain}.cert}";
+          private-key = "file://${certs.${domain}.key}";
+        };
+
+        server.tls = {
+          certificate = "snakeoil";
+          enable = true;
+          implicit = false;
+        };
+
+        server.listener = {
+          "smtp-submission" = {
+            bind = [ "[::]:587" ];
+            protocol = "smtp";
+          };
+
+          "imap" = {
+            bind = [ "[::]:143" ];
+            protocol = "imap";
+          };
+        };
+
+        session.auth.mechanisms = [ "PLAIN" ];
+        session.auth.directory = "in-memory";
+        jmap.directory = "in-memory";  # shared with imap
+
+        session.rcpt.directory = "in-memory";
+        queue.outbound.next-hop = [ "local" ];
+
+        directory."in-memory" = {
+          type = "memory";
+          users = [
+            {
+              name = "alice";
+              secret = "foobar";
+              email = [ "alice@${domain}" ];
+            }
+            {
+              name = "bob";
+              secret = "foobar";
+              email = [ "bob@${domain}" ];
+            }
+          ];
+        };
+      };
+    };
+
+    environment.systemPackages = [
+      (pkgs.writers.writePython3Bin "test-smtp-submission" { } ''
+        from smtplib import SMTP
+
+        with SMTP('localhost', 587) as smtp:
+            smtp.starttls()
+            smtp.login('alice', 'foobar')
+            smtp.sendmail(
+                'alice@${domain}',
+                'bob@${domain}',
+                """
+                    From: alice@${domain}
+                    To: bob@${domain}
+                    Subject: Some test message
+
+                    This is a test message.
+                """.strip()
+            )
+      '')
+
+      (pkgs.writers.writePython3Bin "test-imap-read" { } ''
+        from imaplib import IMAP4
+
+        with IMAP4('localhost') as imap:
+            imap.starttls()
+            imap.login('bob', 'foobar')
+            imap.select('"All Mail"')
+            status, [ref] = imap.search(None, 'ALL')
+            assert status == 'OK'
+            [msgId] = ref.split()
+            status, msg = imap.fetch(msgId, 'BODY[TEXT]')
+            assert status == 'OK'
+            assert msg[0][1].strip() == b'This is a test message.'
+      '')
+    ];
+  };
+
+  testScript = /* python */ ''
+    main.wait_for_unit("stalwart-mail.service")
+    main.wait_for_open_port(587)
+    main.wait_for_open_port(143)
+
+    main.succeed("test-smtp-submission")
+    main.succeed("test-imap-read")
+  '';
+
+  meta = {
+    maintainers = with lib.maintainers; [ happysalada pacien ];
+  };
+})