Move all of NixOS to nixos/ in preparation of the repository merge

nixos/tests/firewall.nix

@@ -0,0 +1,48 @@
+# Test the firewall module.
+
+{ pkgs, ... }:
+
+{
+
+  nodes =
+    { walled =
+        { config, pkgs, nodes, ... }:
+        { networking.firewall.enable = true;
+          networking.firewall.logRefusedPackets = true;
+          services.httpd.enable = true;
+          services.httpd.adminAddr = "foo@example.org";
+        };
+
+      attacker =
+        { config, pkgs, ... }:
+        { services.httpd.enable = true;
+          services.httpd.adminAddr = "foo@example.org";
+        };
+    };
+
+  testScript =
+    { nodes, ... }:
+    ''
+      startAll;
+
+      $walled->waitForUnit("firewall");
+      $walled->waitForUnit("httpd");
+      $attacker->waitForUnit("network.target");
+
+      # Local connections should still work.
+      $walled->succeed("curl -v http://localhost/ >&2");
+
+      # Connections to the firewalled machine should fail.
+      $attacker->fail("curl -v http://walled/ >&2");
+      $attacker->fail("ping -c 1 walled >&2");
+
+      # Outgoing connections/pings should still work.
+      $walled->succeed("curl -v http://attacker/ >&2");
+      $walled->succeed("ping -c 1 attacker >&2");
+
+      # If we stop the firewall, then connections should succeed.
+      $walled->stopJob("firewall");
+      $attacker->succeed("curl -v http://walled/ >&2");
+    '';
+
+}