test: run _demo/* and _pydemo/*

.github/workflows/test_demo.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+# llgo run subdirectories under _demo and _pydemo
+total=0
+failed=0
+failed_cases=""
+for d in ./_demo/* ./_pydemo/*; do
+  total=$((total+1))
+  if [ -d "$d" ]; then
+    echo "Testing $d"
+    if ! llgo run -v "$d"; then
+      echo "FAIL"
+      failed=$((failed+1))
+      failed_cases="$failed_cases\n$d"
+    else
+      echo "PASS"
+    fi
+  fi
+done
+
+echo "=== Done"
+echo "$((total-failed))/$total tests passed"
+if [ "$failed" -ne 0 ]; then
+  echo -e "Failed cases:$failed_cases"
+  exit 1
+fi