fix: return error in test

development/test/cases/util/deadmansswitch.mjs

@@ -9,7 +9,7 @@ describe('DeadMansSwitch', function () {
 
             const ms1 =  Date.now();
 
-            const deadmansswitch = new DeadMansSwitch(100, () => {
+            new DeadMansSwitch(100, () => {
 
                 const ms2 =  Date.now();
 
@@ -38,12 +38,12 @@ describe('DeadMansSwitch', function () {
                 const diff = ms2 - ms1;
 
                 if (ms1 > ms2) {
-                    done('timing error');
+                    done(new Error('timing error'));
                     return;
                 }
 
                 if (diff < 600) {
-                    done('to short ' + diff);
+                    done(new Error('to short ' + diff));
                     return;
                 }
                 done();