修复测试结果检查的语法错误

.gitea/workflows/autograde.yml

@@ -190,9 +190,10 @@ jobs:
           # Collect all JUnit XML reports
           find build/test-results/test -name "TEST-*.xml" -exec cat {} \; > all_tests.xml 2>/dev/null || true
           
-          # Also try to get a single combined report
-          if [ -f build/test-results/test/TEST-*.xml ]; then
-            cp build/test-results/test/TEST-*.xml junit.xml 2>/dev/null || true
+          # Also try to get a single combined report - use ls to check if any test files exist
+          if ls build/test-results/test/TEST-*.xml 1> /dev/null 2>&1; then
+            # If multiple files exist, just copy the first one
+            cp $(ls -1 build/test-results/test/TEST-*.xml | head -1) junit.xml 2>/dev/null || true
           fi
       
       - name: Grade programming tests