test: ui-smoke phase 2, g-code execution and endpoint check

debian/control.top.in

@@ -57,6 +57,7 @@ Build-Depends:
     python3-dbus <!nocheck>,
     python3-dbus.mainloop.pyqt5 <!nocheck>,
     python3-qtpy <!nocheck>,
+    python3-zmq <!nocheck>,
     python3-cairo <!nocheck>,
     python3-gi <!nocheck>,
     python3-gi-cairo <!nocheck>,

tests/ui-smoke/_lib/checkresult-quit.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+# Shared result check for UI smoke quit-path tests.
+#
+# Pass if the quit launcher printed UI_SMOKE_QUIT_OK (the GUI exited on
+# its own SIGTERM within the grace) and did not print UI_SMOKE_QUIT_FAIL.
+set -u
+
+if [ $# -lt 1 ]; then
+    echo "FAIL: checkresult-quit requires the result-log path as argument" >&2
+    exit 1
+fi
+
+LOG="$1"
+
+if grep -q '^UI_SMOKE_QUIT_FAIL' "$LOG"; then
+    echo "FAIL: $(grep -m1 '^UI_SMOKE_QUIT_FAIL' "$LOG")" >&2
+    exit 1
+fi
+
+if ! grep -q '^UI_SMOKE_QUIT_OK' "$LOG"; then
+    echo "FAIL: GUI did not report a clean SIGTERM exit (no UI_SMOKE_QUIT_OK)" >&2
+    exit 1
+fi
+
+exit 0

tests/ui-smoke/_lib/crashdump.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+# Native crash capture for the UI smoke launchers. A GUI segfault is the
+# failure these tests most need to explain, and it lands in C/C++ (Qt,
+# dbus, GL) where PYTHONFAULTHANDLER stops at the event-loop frame. Arm a
+# core dump before launch; after the run, if the GUI left a core, print a
+# native backtrace into the log so CI shows the faulting frame directly.
+# Source with LIB_DIR set; runs only on the failure path, so green runs
+# pay nothing.
+
+crashdump_arm() {
+    CORE_DIR="$(mktemp -d -t ui-smoke-cores.XXXXXX)"
+    export CORE_DIR
+    ulimit -c unlimited 2>/dev/null || true
+    # core_pattern is global and needs root; best-effort (CI has sudo).
+    # If it does not take, crashdump_report still finds a cwd "core".
+    sudo sysctl -w "kernel.core_pattern=$CORE_DIR/core.%e.%p" >/dev/null 2>&1 || true
+}
+
+crashdump_report() {
+    [ -n "${CORE_DIR:-}" ] || return 0
+    local core
+    # shellcheck disable=SC2012  # mktemp dir, no odd filenames
+    core=$(ls -t "$CORE_DIR"/core* ./core* /tmp/core* 2>/dev/null | head -1)
+    if [ -n "$core" ]; then
+        echo "=== crash: native backtrace ($core) ==="
+        # gdb is not on the CI runner by default; pull it in to read the core.
+        command -v gdb >/dev/null 2>&1 || sudo apt-get install -y -q gdb >/dev/null 2>&1 || true
+        if command -v gdb >/dev/null 2>&1; then
+            # "bt" first: gdb auto-selects the faulting thread on a SIGSEGV
+            # core. "thread apply all bt" after gives the rest.
+            gdb -batch -nx \
+                -ex "bt" \
+                -ex "echo \n=== all threads ===\n" \
+                -ex "thread apply all bt" \
+                "$(command -v python3)" "$core" 2>&1 | head -400
+        else
+            echo "(gdb unavailable; core left at $core)"
+        fi
+    fi
+    rm -rf "$CORE_DIR"
+}