nixos/nginx: ensure all variants have a basic level of testing

nixos/tests/nginx-variants.nix

@@ -0,0 +1,33 @@
+{ system ? builtins.currentSystem,
+  config ? {},
+  pkgs ? import ../.. { inherit system config; }
+}:
+
+with import ../lib/testing-python.nix { inherit system pkgs; };
+
+builtins.listToAttrs (
+  builtins.map
+    (nginxName:
+      {
+        name = nginxName;
+        value = makeTest {
+          name = "nginx-variant-${nginxName}";
+
+          machine = { pkgs, ... }: {
+            services.nginx = {
+              enable = true;
+              virtualHosts.localhost.locations."/".return = "200 'foo'";
+              package = pkgs."${nginxName}";
+            };
+          };
+
+          testScript = ''
+            machine.wait_for_unit("nginx")
+            machine.wait_for_open_port(80)
+            machine.succeed('test "$(curl -fvvv http://localhost/)" = foo')
+          '';
+        };
+      }
+    )
+    [ "nginxStable" "nginxUnstable" "nginxShibboleth" "openresty" "tengine" ]
+)