tests/emacs: reorganize darwin and linux

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>

tests/modules/services/emacs/linux/emacs-service-27.nix

@@ -0,0 +1,45 @@
+{ lib, pkgs, ... }:
+
+{
+  nixpkgs.overlays = [
+    (self: super: rec {
+      emacs = pkgs.writeShellScriptBin "dummy-emacs-27.2" "" // {
+        outPath = "@emacs@";
+      };
+      emacsPackagesFor =
+        _:
+        lib.makeScope super.newScope (_: {
+          emacsWithPackages = _: emacs;
+        });
+    })
+  ];
+
+  programs.emacs.enable = true;
+  services.emacs.enable = true;
+  services.emacs.client.enable = true;
+  services.emacs.extraOptions = [
+    "-f"
+    "exwm-enable"
+  ];
+
+  nmt.script = ''
+    assertPathNotExists home-files/.config/systemd/user/emacs.socket
+    assertFileExists home-files/.config/systemd/user/emacs.service
+    assertFileExists home-path/share/applications/emacsclient.desktop
+
+    assertFileContent \
+      home-files/.config/systemd/user/emacs.service \
+      ${pkgs.substitute {
+        src = ./emacs-service-emacs.service;
+        substitutions = [
+          "--replace"
+          "@runtimeShell@"
+          pkgs.runtimeShell
+        ];
+      }}
+
+    assertFileContent \
+      home-path/share/applications/emacsclient.desktop \
+      ${./emacs-27-emacsclient.desktop}
+  '';
+}