micro: add test with expect

pkgs/applications/editors/micro/default.nix

···
-{ lib, buildGoModule, fetchFromGitHub, installShellFiles }:
+{ lib, buildGoModule, fetchFromGitHub, installShellFiles, callPackage }:
 
 buildGoModule rec {
   pname = "micro";
···
     installManPage assets/packaging/micro.1
     install -Dt $out/share/applications assets/packaging/micro.desktop
   '';
+
+  passthru.tests.expect = callPackage ./test-with-expect.nix {};
 
   meta = with lib; {
     homepage = "https://micro-editor.github.io";

pkgs/applications/editors/micro/test-with-expect.nix

···
+{ micro, expect, runCommand, writeScript, runtimeShell }:
+
+let expect-script = writeScript "expect-script" ''
+  #!${expect}/bin/expect -f
+
+  spawn micro file.txt
+  expect "file.txt"
+
+  send "Hello world!"
+  expect "Hello world!"
+
+  # Send ctrl-q (exit)
+  send "\021"
+
+  expect "Save changes to file.txt before closing?"
+  send "y"
+
+  expect eof
+''; in
+runCommand "micro-test-expect"
+{
+  nativeBuildInputs = [ micro expect ];
+  passthru = { inherit expect-script; };
+} ''
+  # Micro really wants a writable $HOME for its config directory.
+  export HOME=$(pwd)
+  expect -f ${expect-script}
+  grep "Hello world!" file.txt
+  touch $out
+''