fix error of false positive

src/test/TestBase.java

@@ -235,14 +235,15 @@ public abstract class TestBase {
                         failAndLog(testPair.getFailMessage(output));
                     }
                     break;
-                case NO_CHECK:
-                    break;
                 case CHECK_FOR_NO_OUTPUT:
-                    if (testPair.getOutput() != null) {
+                    if (output != null) {
                         log.info(" Failed!\n");
                         printLog();
                         fail("Output should have been empty but was:" + output);
                     }
+
+                    break;
+                case NO_CHECK:
                     break;
                 default:
                     fail("Unimplemented error check");