Improve Otlp Delta Aggregation with support for max and Histogram.

Author: lenin-jaganathan

micrometer-core/src/main/java/io/micrometer/core/instrument/step/StepMax.java

@@ -52,4 +52,5 @@ public void record(double value) {
     public void _closingRollover() {
         super.closingRollover();
     }
+
 }

micrometer-core/src/test/java/io/micrometer/core/instrument/step/StepMaxTest.java

@@ -1,18 +1,41 @@
+/*
+ * Copyright 2023 VMware, Inc.
+ *
+ * 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
+ *
+ * https://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 io.micrometer.core.instrument.step;
 
 import io.micrometer.core.instrument.MockClock;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import java.time.Duration;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 class StepMaxTest {
+
     private final Duration step = Duration.ofMillis(10);
+
     MockClock clock;
+
+    @BeforeEach
+    void init() {
+        clock = new MockClock();
+    }
+
     @Test
     void testMax() {
-        clock = new MockClock();
         StepMax max = new StepMax(clock, step.toMillis());
 
         assertThat(max.poll()).isZero();
@@ -32,7 +55,6 @@ void testMax() {
 
     @Test
     void shouldPreserveCurrentAfterManualRollover() {
-        clock = new MockClock();
         StepMax max = new StepMax(clock, step.toMillis());
 
         max.record(11);
@@ -45,4 +67,5 @@ void shouldPreserveCurrentAfterManualRollover() {
         clock.add(step);
         assertThat(max.poll()).isEqualTo(11);
     }
+
 }