@Test
  public void createWithSystem_throwsNullPointerException_ifSystemIsNull() {
    InternalCacheBuilder internalCacheBuilder = new InternalCacheBuilder(
        new Properties(), new CacheConfig(), metricsSessionBuilder, THROWING_SYSTEM_SUPPLIER,
        THROWING_SYSTEM_CONSTRUCTOR,
        THROWING_CACHE_SUPPLIER, THROWING_CACHE_CONSTRUCTOR);

    Throwable thrown = catchThrowable(() -> internalCacheBuilder.create(null));

    assertThat(thrown).isInstanceOf(NullPointerException.class);
  }
Unit tests for {@link InternalCacheBuilder} when
{@code InternalDistributedSystem.ALLOW_MULTIPLE_SYSTEMS} is set to true.
geode-core/src/test/java/org/apache/geode/internal/cache/InternalCacheBuilderAllowsMultipleSystemsTest.java