@Test void doesNotProvidesCollectorComponent_whenUrlSetAndDisabled() {
    TestPropertyValues.of("zipkin.collector.activemq.url:tcp://localhost:61616")
      .applyTo(context);
    TestPropertyValues.of("zipkin.collector.activemq.enabled:false").applyTo(context);
    context.register(
      PropertyPlaceholderAutoConfiguration.class,
      ZipkinActiveMQCollectorConfiguration.class,
      InMemoryConfiguration.class);
    context.refresh();

    assertThatThrownBy(() -> context.getBean(ActiveMQCollector.class))
      .isInstanceOf(NoSuchBeanDefinitionException.class);
  }
This prevents an empty ACTIVEMQ_URL variable from being mistaken as a real one
zipkin-server/src/test/java/zipkin2/server/internal/activemq/ZipkinActiveMQCollectorPropertiesTest.java