diff --git a/Justfile b/Justfile
index 3be1ee1..2d12c0e 100644
--- a/Justfile
+++ b/Justfile
@@ -101,52 +101,80 @@ ci *args: check-craftos check
     @just test-timeout
 
 # Run CraftOS-PC headless integration tests. Pass `--pretty` for grouped output.
+[positional-arguments]
 test *args:
-	@if [ -f .env.test ]; then set -a; . ./.env.test; set +a; fi; \
-	pretty=0; \
-	verbose=0; \
-	timeout_seconds="${TRAP_CCLIBS_TEST_TIMEOUT_SECONDS:-3}"; \
-	case "$timeout_seconds" in ''|*[!0-9]*) printf '%s\n' 'TRAP_CCLIBS_TEST_TIMEOUT_SECONDS must be a positive integer' >&2; exit 1 ;; esac; \
-	if [ "$timeout_seconds" -lt 1 ]; then printf '%s\n' 'TRAP_CCLIBS_TEST_TIMEOUT_SECONDS must be >= 1' >&2; exit 1; fi; \
-	for a in {{args}}; do case "$a" in --pretty) pretty=1 ;; --verbose|-v) pretty=1; verbose=1 ;; esac; done; \
-	rom_arg=""; \
-	if [ "$(uname -s)" = "Darwin" ]; then \
-		rom_arg="--rom /Applications/CraftOS-PC.app/Contents/Resources"; \
-	fi; \
-	repo='{{justfile_directory()}}'; \
-	mount_arg="--mount-ro /apis=$repo/apis --mount-ro /programs=$repo/programs --mount-ro /startup=$repo/startup --mount-ro /tests=$repo/tests"; \
-	tmp="$(mktemp)"; \
-	data_dir="$(mktemp -d)"; \
-	output_path="$data_dir/computer/0/trapos-test-output"; \
-	exec_code="shell.run('/programs/runtest.lua', '--shutdown')"; \
-	if [ "$pretty" -eq 1 ]; then exec_code="shell.run('/programs/runtest.lua', '--pretty', '--output', '/trapos-test-output', '--shutdown')"; fi; \
-	if [ "$verbose" -eq 1 ]; then exec_code="shell.run('/programs/runtest.lua', '--verbose', '--output', '/trapos-test-output', '--shutdown')"; fi; \
-	craftos --directory "$data_dir" --headless $rom_arg $mount_arg --exec "$exec_code" >"$tmp" 2>&1 & \
-	pid="$!"; \
-	( sleep "$timeout_seconds"; kill -TERM "$pid" >/dev/null 2>&1 ) & \
-	watchdog="$!"; \
-	wait "$pid" >/dev/null 2>&1; \
-	status="$?"; \
-	kill "$watchdog" >/dev/null 2>&1 || true; \
-	wait "$watchdog" >/dev/null 2>&1 || true; \
-	if grep -q __TRAPOS_TEST_OK__ "$tmp"; then \
-		if [ "$pretty" -eq 1 ] && [ -f "$output_path" ]; then cat "$output_path"; fi; \
-		rm -f "$tmp"; \
-		rm -rf "$data_dir"; \
-	else \
-		red=$(printf '\033[31m'); reset=$(printf '\033[0m'); \
-		if [ "$status" -eq 143 ]; then \
-			printf '%s\n' "${red}FAIL${reset} CraftOS integration tests timed out after ${timeout_seconds}s" >&2; \
-		else \
-			printf '%s\n' "${red}FAIL${reset} CraftOS integration tests did not print __TRAPOS_TEST_OK__" >&2; \
-		fi; \
-		if [ -f "$output_path" ]; then cat "$output_path" >&2; fi; \
-		cat "$tmp" >&2; \
-		rm -f "$tmp"; \
-		rm -rf "$data_dir"; \
-		exit 1; \
-	fi; \
-	printf '%s\n' 'OK: CraftOS integration tests passed'
+    #!/usr/bin/env bash
+    set -uo pipefail
+
+    if [ -f .env.test ]; then set -a; . ./.env.test; set +a; fi
+
+    pretty=0
+    has_output=0
+    timeout_seconds="${TRAP_CCLIBS_TEST_TIMEOUT_SECONDS:-3}"
+    case "$timeout_seconds" in ''|*[!0-9]*) printf '%s\n' 'TRAP_CCLIBS_TEST_TIMEOUT_SECONDS must be a positive integer' >&2; exit 1 ;; esac
+    if [ "$timeout_seconds" -lt 1 ]; then printf '%s\n' 'TRAP_CCLIBS_TEST_TIMEOUT_SECONDS must be >= 1' >&2; exit 1; fi
+
+    runtest_args=("$@")
+    for a in "$@"; do
+        case "$a" in
+            --pretty|--verbose|-v) pretty=1 ;;
+            --output) has_output=1 ;;
+        esac
+    done
+    if [ "$pretty" -eq 1 ] && [ "$has_output" -eq 0 ]; then
+        runtest_args+=(--output /trapos-test-output)
+    fi
+    runtest_args+=(--shutdown)
+
+    lua_quote() {
+        local value="$1"
+        value="${value//\\/\\\\}"
+        value="${value//\'/\\\'}"
+        printf "'%s'" "$value"
+    }
+
+    exec_code="shell.run('/programs/runtest.lua'"
+    for arg in "${runtest_args[@]}"; do
+        exec_code+=", $(lua_quote "$arg")"
+    done
+    exec_code+=")"
+
+    rom_arg=()
+    if [ "$(uname -s)" = "Darwin" ]; then
+        rom_arg=(--rom /Applications/CraftOS-PC.app/Contents/Resources)
+    fi
+    repo='{{justfile_directory()}}'
+    mount_arg=(--mount-ro "/apis=$repo/apis" --mount-ro "/programs=$repo/programs" --mount-ro "/startup=$repo/startup" --mount-ro "/tests=$repo/tests")
+    tmp="$(mktemp)"
+    data_dir="$(mktemp -d)"
+    output_path="$data_dir/computer/0/trapos-test-output"
+
+    craftos --directory "$data_dir" --headless "${rom_arg[@]}" "${mount_arg[@]}" --exec "$exec_code" >"$tmp" 2>&1 &
+    pid="$!"
+    ( sleep "$timeout_seconds"; kill -TERM "$pid" >/dev/null 2>&1 ) &
+    watchdog="$!"
+    wait "$pid" >/dev/null 2>&1
+    status="$?"
+    kill "$watchdog" >/dev/null 2>&1 || true
+    wait "$watchdog" >/dev/null 2>&1 || true
+    if grep -q __TRAPOS_TEST_OK__ "$tmp"; then
+        if [ "$pretty" -eq 1 ] && [ -f "$output_path" ]; then cat "$output_path"; fi
+        rm -f "$tmp"
+        rm -rf "$data_dir"
+    else
+        red=$(printf '\033[31m'); reset=$(printf '\033[0m')
+        if [ "$status" -eq 143 ]; then
+            printf '%s\n' "${red}FAIL${reset} CraftOS integration tests timed out after ${timeout_seconds}s" >&2
+        else
+            printf '%s\n' "${red}FAIL${reset} CraftOS integration tests did not print __TRAPOS_TEST_OK__" >&2
+        fi
+        if [ -f "$output_path" ]; then cat "$output_path" >&2; fi
+        cat "$tmp" >&2
+        rm -f "$tmp"
+        rm -rf "$data_dir"
+        exit 1
+    fi
+    printf '%s\n' 'OK: CraftOS integration tests passed'
 
 # Harness self-test: run a tests/harness fixture and assert which timeout layer
 # caught it. `expect` is "lua" (libtest cancels the case) or "shell" (the shell