content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.metrics;
  
  import org.junit.Test;
  
  import static org.assertj.core.api.Assertions.assertThat;
  
  public class DerivativeGaugeTest {
      private final Gauge<String> gauge1 = new Gauge<String>() {
          @Override
          public String getValue() {
              return "woo";
          }
          @Override
          public long lastUpdateTime() {
              return 0;
          }
      };
      private final Gauge<Integer> gauge2 = new DerivativeGauge<String, Integer>(gauge1) {
          @Override
          protected Integer transform(String value) {
              return value.length();
          }
      };
  
      @Test
      public void returnsATransformedValue() throws Exception {
          assertThat(gauge2.getValue())
                  .isEqualTo(3);
      }
  }
  