nixos/dnscrypt-proxy: fix apparmor profile and test

Test failed because of an incomplete apparmor profile.
- fix apparmor profile
- improve test timing, prevent non-deterministic failure

nixos/modules/services/networking/dnscrypt-proxy.nix

@@ -192,6 +192,7 @@ in
     security.apparmor.profiles = singleton (pkgs.writeText "apparmor-dnscrypt-proxy" ''
       ${pkgs.dnscrypt-proxy}/bin/dnscrypt-proxy {
         /dev/null rw,
+        /dev/random r,
         /dev/urandom r,
 
         /etc/passwd r,
@@ -211,6 +212,9 @@ in
         ${getLib pkgs.gcc.cc}/lib/libssp.so.* mr,
         ${getLib pkgs.libsodium}/lib/libsodium.so.* mr,
         ${getLib pkgs.systemd}/lib/libsystemd.so.* mr,
+        ${getLib pkgs.utillinuxMinimal.out}/lib/libmount.so.* mr,
+        ${getLib pkgs.utillinuxMinimal.out}/lib/libblkid.so.* mr,
+        ${getLib pkgs.utillinuxMinimal.out}/lib/libuuid.so.* mr,
         ${getLib pkgs.xz}/lib/liblzma.so.* mr,
         ${getLib pkgs.libgcrypt}/lib/libgcrypt.so.* mr,
         ${getLib pkgs.libgpgerror}/lib/libgpg-error.so.* mr,

nixos/tests/dnscrypt-proxy.nix

@@ -26,7 +26,8 @@ import ./make-test.nix ({ pkgs, ... }: {
     $client->waitForUnit("dnsmasq");
 
     # The daemon is socket activated; sending a single ping should activate it.
+    $client->fail("systemctl is-active dnscrypt-proxy");
     $client->execute("${pkgs.iputils}/bin/ping -c1 example.com");
-    $client->succeed("systemctl is-active dnscrypt-proxy");
+    $client->waitUntilSucceeds("systemctl is-active dnscrypt-proxy");
   '';
 })