Cleans up test.

tests/hello.nix

@@ -1,15 +1,15 @@
 {pkgs, ...}: {
   name = "hello";
   nodes = {
-    machine1 = {pkgs, ...}: {
+    machine = {pkgs, ...}: {
       imports = [../machines/hello.nix];
       environment.systemPackages = [pkgs.hello];
     };
   };
   testScript = ''
     start_all()
-    machine1.wait_for_unit("sshd.service")
-    machine1.succeed("hello")
-    machine1.fail("hello")
+    machine.wait_for_unit("sshd.service")
+    machine.succeed("hello")
+    machine.succeed("ssh-keygen -t rsa -N ''' -f ~/.ssh/id_rsa")
   '';
 }