Install QEMU's virtio-vga display and check for it

The smoketest VMs start with -vga virtio, but Arch packages that display
apart from qemu-base, so the base image build failed with "Virtio VGA not
available". update.sh now installs qemu-hw-display-virtio-vga, and doctor
and smoketest run check QEMU has the display before anything downloads.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/doctor.bats

@@ -71,3 +71,15 @@ load test_helper
   [[ "$output" == *"Usage: coredesktop-dev doctor"* ]]
   not_called flatpak-spawn
 }
+
+@test "doctor reports QEMU without the virtio-vga display" {
+  make_working_copy
+  stub qemu-system-x86_64 'echo "name \"VGA\", bus PCI"'
+  run cdd doctor
+  [ "$status" -eq 1 ]
+  [[ "$output" == *"PROBLEM  QEMU has no virtio-vga display"* ]]
+
+  stub qemu-system-x86_64 'echo "name \"virtio-vga\", bus PCI"'
+  run cdd doctor
+  [[ "$output" == *"ok       QEMU has the virtio-vga display"* ]]
+}

tests/install.bats

@@ -14,7 +14,7 @@ config() {
   [[ "$output" == *"is the deployed copy"* ]]
   [ "$(config)" = "WORKING_COPY=$(printf '%q' "$WC")" ]
   [ "$(readlink "$HOME/.local/bin/coredesktop-dev")" = "$PROJECT/bin/coredesktop-dev" ]
-  called install_packages shellcheck bats tea qemu-base libisoburn
+  called install_packages shellcheck bats tea qemu-base qemu-hw-display-virtio-vga libisoburn
 }
 
 @test "install refuses the deployed copy however it's spelled" {

tests/smoketest.bats

@@ -18,7 +18,8 @@ setup() {
   git -C "$WC" rev-parse HEAD > "$STATE/images/installed.ref"
 
   # A VM is a sleep that lets go of bats' output pipes
-  stub qemu-system-x86_64 'while [ $# -gt 0 ]; do [ "$1" = -pidfile ] && pidfile="$2"; shift; done
+  stub qemu-system-x86_64 '[ "$*" = "-device help" ] && { echo "name \"virtio-vga\", bus PCI"; exit; }
+    while [ $# -gt 0 ]; do [ "$1" = -pidfile ] && pidfile="$2"; shift; done
     /usr/bin/sleep 300 > /dev/null 2>&1 3>&- &
     echo $! > "$pidfile"'
   stub qemu-img 'touch "${@: -1}"'
@@ -98,7 +99,16 @@ last_run() {
   run cdd smoketest run 10 nosuch
   [ "$status" -eq 1 ]
   [[ "$output" == *"No scenario called nosuch"* ]]
-  not_called qemu-system-x86_64
+  # Only the check for the virtio-vga display, no VM
+  [ -z "$(grep '^qemu-system-x86_64 ' "$STUB_LOG" | grep -v -- '-device help')" ]
+}
+
+@test "run stops before any VM when QEMU has no virtio-vga display" {
+  stub qemu-system-x86_64 'echo "name \"VGA\", bus PCI"'
+  run cdd smoketest run 10
+  [ "$status" -eq 1 ]
+  [[ "$output" == *"QEMU has no virtio-vga display"* ]]
+  [ "$(grep -c '^qemu-system-x86_64 ' "$STUB_LOG")" -eq 1 ]
 }
 
 @test "each variant runs in its own VM" {
@@ -106,7 +116,7 @@ last_run() {
   [ "$status" -eq 0 ]
   [[ "$output" == *"PASS  30-variants @ one"* ]]
   [[ "$output" == *"PASS  30-variants @ two"* ]]
-  [ "$(grep -c '^qemu-system-x86_64 ' "$STUB_LOG")" -eq 2 ]
+  [ "$(grep '^qemu-system-x86_64 ' "$STUB_LOG" | grep -vc -- '-device help')" -eq 2 ]
   grep -q "variant two" "$(last_run)/30-variants@two/scenario.log"
 }
 

tests/update.bats

@@ -7,7 +7,7 @@ HOOK_MARKER="# Installed by coredesktop-dev; remove with: coredesktop-dev hooks
 @test "update installs the packages and links the command, without asking anything" {
   run bash "$PROJECT/update.sh" < /dev/null
   [ "$status" -eq 0 ]
-  called install_packages shellcheck bats tea qemu-base libisoburn
+  called install_packages shellcheck bats tea qemu-base qemu-hw-display-virtio-vga libisoburn
   [ "$(readlink "$HOME/.local/bin/coredesktop-dev")" = "$PROJECT/bin/coredesktop-dev" ]
 }