ConnPoolMetersAsyncTest.java

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package org.apache.hc.client5.http.observation.binder;

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;

import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
import org.apache.hc.client5.http.impl.async.HttpAsyncClientBuilder;
import org.apache.hc.client5.http.impl.async.HttpAsyncClients;
import org.apache.hc.client5.http.impl.nio.PoolingAsyncClientConnectionManagerBuilder;
import org.apache.hc.client5.http.nio.AsyncClientConnectionManager;
import org.junit.jupiter.api.Test;

class ConnPoolMetersAsyncTest {

    @Test
    void registersGaugesWhenAsyncPoolPresent() throws Exception {
        final MeterRegistry reg = new SimpleMeterRegistry();

        final AsyncClientConnectionManager cm = PoolingAsyncClientConnectionManagerBuilder.create().build();
        final HttpAsyncClientBuilder b = HttpAsyncClients.custom().setConnectionManager(cm);

        ConnPoolMetersAsync.bindTo(b, reg);

        // build to finalize builder configuration
        b.build().close();

        assertNotNull(reg.find("http.client.pool.leased").gauge());
        assertNotNull(reg.find("http.client.pool.available").gauge());
        assertNotNull(reg.find("http.client.pool.pending").gauge());
    }

    @Test
    void noExceptionIfNoAsyncPool() {
        final MeterRegistry reg = new SimpleMeterRegistry();
        final HttpAsyncClientBuilder b = HttpAsyncClients.custom(); // no CM set
        ConnPoolMetersAsync.bindTo(b, reg);
        assertNull(reg.find("http.client.pool.leased").gauge());
    }
}