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Testing Micrometer Metrics Integration in HikariCP

This test suite validates the Micrometer metrics integration with HikariCP’s connection pool monitoring system. It ensures proper registration and tracking of various connection pool metrics through Micrometer’s MeterRegistry implementation. The tests verify the presence and configuration of essential connection pool metrics.

Test Coverage Overview

The test suite provides comprehensive coverage of HikariCP’s connection pool metrics integration with Micrometer.

Validates registration of connection acquisition timers
Tests connection usage and creation metric tracking
Verifies timeout counter implementation
Confirms proper gauge metrics for pool statistics

Implementation Analysis

The testing approach utilizes JUnit framework with a mock MeterRegistry implementation via SimpleMeterRegistry. The test structure employs the standard setup-execute-verify pattern, with a focused test method validating multiple metric registrations. StubPoolStats provides simulated pool statistics for testing.

Technical Details

JUnit testing framework
Micrometer Core for metrics instrumentation
SimpleMeterRegistry for metrics collection
StubPoolStats for connection pool simulation
Assert methods for verification

Best Practices Demonstrated

The test implementation showcases several testing best practices including proper test setup isolation, mock object usage, and comprehensive metric verification. The code organization follows a clear pattern with setup methods and focused test cases. The use of descriptive metric names and appropriate tags demonstrates good monitoring practices.

brettwooldridge/hikaricp

src/test/java/com/zaxxer/hikari/metrics/micrometer/MicrometerMetricsTrackerTest.java

            
package com.zaxxer.hikari.metrics.micrometer;

import com.zaxxer.hikari.mocks.StubPoolStats;
import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

public class MicrometerMetricsTrackerTest
{

   private MeterRegistry mockMeterRegistry = new SimpleMeterRegistry();

   private MicrometerMetricsTracker testee;

   @Before
   public void setup()
   {
      testee = new MicrometerMetricsTracker("mypool", new StubPoolStats(1000L), mockMeterRegistry);
   }

   @Test
   public void close()
   {
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.acquire").tag("pool", "mypool").timer());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.usage").tag("pool", "mypool").timer());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.creation").tag("pool", "mypool").timer());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.timeout").tag("pool", "mypool").counter());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections").tag("pool", "mypool").gauge());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.idle").tag("pool", "mypool").gauge());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.active").tag("pool", "mypool").gauge());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.pending").tag("pool", "mypool").gauge());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.max").tag("pool", "mypool").gauge());
      Assert.assertNotNull(mockMeterRegistry.find("hikaricp.connections.min").tag("pool", "mypool").gauge());

      testee.close();
   }
}