@BeforeEach
    public void setup() {
        logContext = new LogContext();

        Properties p = new Properties();
        p.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        p.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        p.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        ConsumerConfig config = new ConsumerConfig(p);

        Metrics metrics = createMetrics(config, time);
        shareFetchMetricsManager = createShareFetchMetricsManager(metrics);
    }
This tests the {@link ShareFetchBuffer} functionality.
One of the main concerns of these tests are that we correctly handle both places that data is held internally:

<ol>
    <li>A special "next in line" buffer</li>
    <li>The remainder of the buffers in a queue</li>
</ol>
clients/src/test/java/org/apache/kafka/clients/consumer/internals/ShareFetchBufferTest.java