test: Fix unstable test cases in MetricExitCallbackTest

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-core/src/test/java/com/alibaba/csp/sentinel/metric/extension/callback/MetricExitCallbackTest.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.alibaba.csp.sentinel.metric.extension.callback;
 
 import com.alibaba.csp.sentinel.Entry;
@@ -5,18 +20,18 @@ import com.alibaba.csp.sentinel.EntryType;
 import com.alibaba.csp.sentinel.context.Context;
 import com.alibaba.csp.sentinel.metric.extension.MetricExtensionProvider;
 import com.alibaba.csp.sentinel.slotchain.StringResourceWrapper;
-import com.alibaba.csp.sentinel.util.TimeUtil;
+import com.alibaba.csp.sentinel.test.AbstractTimeBasedTest;
 
 import org.junit.Assert;
 import org.junit.Test;
 
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
+import static org.powermock.api.mockito.PowerMockito.mock;
+import static org.powermock.api.mockito.PowerMockito.when;
 
 /**
  * @author Carpenter Lee
  */
-public class MetricExitCallbackTest {
+public class MetricExitCallbackTest extends AbstractTimeBasedTest {
 
     @Test
     public void onExit() {
@@ -27,17 +42,24 @@ public class MetricExitCallbackTest {
         StringResourceWrapper resourceWrapper = new StringResourceWrapper("resource", EntryType.OUT);
         int count = 2;
         Object[] args = {"args1", "args2"};
-        extension.rt = 20;
+        long prevRt = 20;
+        extension.rt = prevRt;
         extension.success = 6;
         extension.thread = 10;
         Context context = mock(Context.class);
         Entry entry = mock(Entry.class);
+
+        // Mock current time
+        long curMillis = System.currentTimeMillis();
+        setCurrentMillis(curMillis);
+
+        int deltaMs = 100;
         when(entry.getError()).thenReturn(null);
-        when(entry.getCreateTime()).thenReturn(TimeUtil.currentTimeMillis() - 100);
+        when(entry.getCreateTime()).thenReturn(curMillis - deltaMs);
         when(context.getCurEntry()).thenReturn(entry);
         exitCallback.onExit(context, resourceWrapper, count, args);
-        Assert.assertEquals(120, extension.rt, 10);
+        Assert.assertEquals(prevRt + deltaMs, extension.rt);
         Assert.assertEquals(extension.success, 6 + count);
         Assert.assertEquals(extension.thread, 10 - 1);
     }
-}
+}