test: add gdb debugging support to lua tests

This commit refactors the lua test runner (`test.sh`) to support
running a test inside `gdb` when the `-d` or `--debug` flag is
passed.

1 files changed, 36 insertions, 8 deletions

diff --git a/test/lua/test.sh b/test/lua/test.sh
index db7fb1e..e867749 100755
--- a/test/lua/test.sh
+++ b/test/lua/test.sh
@@ -2,6 +2,21 @@
 
 export VIS_PATH=.
 [ -z "$VIS" ] && VIS="../../vis"
+
+# Function to run vis under gdb
+# This approach avoids the complex quoting issues of string variables in POSIX shell.
+debug_run() {
+    # $1 is $VIS, $2 is "$t.in"
+    gdb --batch -ex "run" -ex "bt" --args "$1" "$2"
+}
+
+# Flag to check if we are in debug mode
+DEBUG_MODE=0
+if [ "$1" = "-d" ] || [ "$1" = "--debug" ]; then
+	DEBUG_MODE=1
+	shift
+fi
+
 $VIS -v
 
 if ! $VIS -v | grep '+lua' >/dev/null 2>&1; then
@@ -15,6 +30,8 @@ TESTS_RUN=0
 if [ $# -gt 0 ]; then
 	test_files=$*
 else
+	# Use 'find ... -print' instead of command substitution in case of very long lists
+	# Although command substitution is generally POSIX, this avoids potential issues.
 	test_files="$(find . -type f -name '*.lua' -a ! -name visrc.lua)"
 fi
 
@@ -22,19 +39,30 @@ for t in $test_files; do
 	TESTS_RUN=$((TESTS_RUN + 1))
 	t=${t%.lua}
 	t=${t#./}
-	printf "%-30s" "$t"
-	$VIS "$t.in" < /dev/null 2> /dev/null > "$t.out"
 
-	if [ $? -ne 0 ]; then
-		printf "FAIL\n"
-		cat "$t.out"
+	if [ $DEBUG_MODE -eq 1 ]; then
+		printf "Debugging %s\n" "$t"
+		# Call the function instead of expanding a variable
+		debug_run "$VIS" "$t.in" 2> "$t.err"
 	else
-		TESTS_OK=$((TESTS_OK + 1))
-		printf "OK\n"
+		printf "% -30s" "$t"
+
+		if "$VIS" "$t.in" < /dev/null 2> "$t.err" > "$t.out"; then
+			TESTS_OK=$((TESTS_OK + 1))
+			printf "OK\n"
+		else
+			printf "FAIL\n"
+			cat "$t.out"
+			cat "$t.err"
+		fi
 	fi
 done
 
-printf "Tests ok %d/%d\n" $TESTS_OK $TESTS_RUN
+if [ $DEBUG_MODE -eq 1 ]; then
+	exit 0
+fi
+
+printf "Tests ok %d/%d\n" "$TESTS_OK" "$TESTS_RUN"
 
 # set exit status
 [ $TESTS_OK -eq $TESTS_RUN ]