nixos/tests: add integration tests for terminal emulators

nixos/tests/all-tests.nix

@@ -521,6 +521,7 @@ in
   telegraf = handleTest ./telegraf.nix {};
   teleport = handleTest ./teleport.nix {};
   thelounge = handleTest ./thelounge.nix {};
+  terminal-emulators = handleTest ./terminal-emulators.nix {};
   tiddlywiki = handleTest ./tiddlywiki.nix {};
   tigervnc = handleTest ./tigervnc.nix {};
   timezone = handleTest ./timezone.nix {};

nixos/tests/terminal-emulators.nix

@@ -0,0 +1,206 @@
+# Terminal emulators all present a pretty similar interface.
+# That gives us an opportunity to easily test their basic functionality with a single codebase.
+#
+# There are two tests run on each terminal emulator
+# - can it successfully execute a command passed on the cmdline?
+# - can it successfully display a colour?
+# the latter is used as a proxy for "can it display text?", without going through all the intricacies of OCR.
+#
+# 256-colour terminal mode is used to display the test colour, since it has a universally-applicable palette (unlike 8- and 16- colour, where the colours are implementation-defined), and it is widely supported (unlike 24-bit colour).
+#
+# Future work:
+# - Wayland support (both for testing the existing terminals, and for testing wayland-only terminals like foot and havoc)
+# - Test keyboard input? (skipped for now, to eliminate the possibility of race conditions and focus issues)
+
+{ system ? builtins.currentSystem,
+  config ? {},
+  pkgs ? import ../.. { inherit system config; }
+}:
+
+with import ../lib/testing-python.nix { inherit system pkgs; };
+with pkgs.lib;
+
+let tests = {
+      alacritty.pkg = p: p.alacritty;
+
+      contour.pkg = p: p.contour;
+      contour.cmd = "contour $command";
+
+      cool-retro-term.pkg = p: p.cool-retro-term;
+      cool-retro-term.colourTest = false; # broken by gloss effect
+
+      ctx.pkg = p: p.ctx;
+      ctx.pinkValue = "#FE0065";
+
+      darktile.pkg = p: p.darktile;
+
+      eterm.pkg = p: p.eterm;
+      eterm.executable = "Eterm";
+      eterm.pinkValue = "#D40055";
+
+      germinal.pkg = p: p.germinal;
+
+      gnome-terminal.pkg = p: p.gnome.gnome-terminal;
+
+      guake.pkg = p: p.guake;
+      guake.cmd = "SHELL=$command guake --show";
+      guake.kill = true;
+
+      hyper.pkg = p: p.hyper;
+
+      kermit.pkg = p: p.kermit-terminal;
+
+      kgx.pkg = p: p.kgx;
+      kgx.cmd = "kgx -e $command";
+      kgx.kill = true;
+
+      kitty.pkg = p: p.kitty;
+      kitty.cmd = "kitty $command";
+
+      konsole.pkg = p: p.plasma5Packages.konsole;
+
+      lxterminal.pkg = p: p.lxterminal;
+
+      mate-terminal.pkg = p: p.mate.mate-terminal;
+      mate-terminal.cmd = "SHELL=$command mate-terminal --disable-factory"; # factory mode uses dbus, and we don't have a proper dbus session set up
+
+      mlterm.pkg = p: p.mlterm;
+
+      mrxvt.pkg = p: p.mrxvt;
+
+      qterminal.pkg = p: p.lxqt.qterminal;
+      qterminal.kill = true;
+
+      roxterm.pkg = p: p.roxterm;
+      roxterm.cmd = "roxterm -e $command";
+
+      sakura.pkg = p: p.sakura;
+
+      st.pkg = p: p.st;
+
+      stupidterm.pkg = p: p.stupidterm;
+      stupidterm.cmd = "stupidterm -- $command";
+
+      terminator.pkg = p: p.terminator;
+      terminator.cmd = "terminator -e $command";
+
+      terminology.pkg = p: p.enlightenment.terminology;
+      terminology.cmd = "SHELL=$command terminology --no-wizard=true";
+      terminology.colourTest = false; # broken by gloss effect
+
+      termite.pkg = p: p.termite;
+
+      termonad.pkg = p: p.termonad;
+
+      tilda.pkg = p: p.tilda;
+
+      tilix.pkg = p: p.tilix;
+      tilix.cmd = "tilix -e $command";
+
+      urxvt.pkg = p: p.rxvt-unicode;
+
+      wayst.pkg = p: p.wayst;
+      wayst.pinkValue = "#FF0066";
+
+      wezterm.pkg = p: p.wezterm;
+
+      xfce4-terminal.pkg = p: p.xfce.xfce4-terminal;
+
+      xterm.pkg = p: p.xterm;
+    };
+in mapAttrs (name: { pkg, executable ? name, cmd ? "SHELL=$command ${executable}", colourTest ? true, pinkValue ? "#FF0087", kill ? false }: makeTest
+{
+  name = "terminal-emulator-${name}";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ jjjollyjim ];
+  };
+
+  machine = { pkgsInner, ... }:
+
+  {
+    imports = [ ./common/x11.nix ./common/user-account.nix ];
+
+    # Hyper (and any other electron-based terminals) won't run as root
+    test-support.displayManager.auto.user = "alice";
+
+    environment.systemPackages = [
+      (pkg pkgs)
+      (pkgs.writeShellScriptBin "report-success" ''
+        echo 1 > /tmp/term-ran-successfully
+        ${optionalString kill "pkill ${executable}"}
+      '')
+      (pkgs.writeShellScriptBin "display-colour" ''
+        # A 256-colour background colour code for pink, then spaces.
+        #
+        # Background is used rather than foreground to minimize the effect of anti-aliasing.
+        #
+        # Keep adding more in case the window is partially offscreen to the left or requires
+        # a change to correctly redraw after initialising the window (as with ctx).
+
+        while :
+        do
+            echo -ne "\e[48;5;198m                   "
+            sleep 0.5
+        done
+        sleep infinity
+      '')
+      (pkgs.writeShellScriptBin "run-in-this-term" "sudo -u alice run-in-this-term-wrapped $1")
+
+      (pkgs.writeShellScriptBin "run-in-this-term-wrapped" "command=\"$(which \"$1\")\"; ${cmd}")
+    ];
+
+    # Helpful reminder to add this test to passthru.tests
+    warnings = if !((pkg pkgs) ? "passthru" && (pkg pkgs).passthru ? "tests") then [ "The package for ${name} doesn't have a passthru.tests" ] else [ ];
+  };
+
+  # We need imagemagick, though not tesseract
+  enableOCR = true;
+
+  testScript = { nodes, ... }: let
+  in ''
+    with subtest("wait for x"):
+        start_all()
+        machine.wait_for_x()
+
+    with subtest("have the terminal run a command"):
+        # We run this command synchronously, so we can be certain the exit codes are happy
+        machine.${if kill then "execute" else "succeed"}("run-in-this-term report-success")
+        machine.wait_for_file("/tmp/term-ran-successfully")
+    ${optionalString colourTest ''
+
+    import tempfile
+    import subprocess
+
+
+    def check_for_pink(final=False) -> bool:
+        with tempfile.NamedTemporaryFile() as tmpin:
+            machine.send_monitor_command("screendump {}".format(tmpin.name))
+
+            cmd = 'convert {} -define histogram:unique-colors=true -format "%c" histogram:info:'.format(
+                tmpin.name
+            )
+            ret = subprocess.run(cmd, shell=True, capture_output=True)
+            if ret.returncode != 0:
+                raise Exception(
+                    "image analysis failed with exit code {}".format(ret.returncode)
+                )
+
+            text = ret.stdout.decode("utf-8")
+            return "${pinkValue}" in text
+
+
+    with subtest("ensuring no pink is present without the terminal"):
+        assert (
+            check_for_pink() == False
+        ), "Pink was present on the screen before we even launched a terminal!"
+
+    with subtest("have the terminal display a colour"):
+        # We run this command in the background
+        machine.shell.send(b"(run-in-this-term display-colour |& systemd-cat -t terminal) &\n")
+
+        with machine.nested("Waiting for the screen to have pink on it:"):
+            retry(check_for_pink)
+  ''}'';
+}
+
+  ) tests