@Test
  public void create_throwsNullPointerException_ifConfigPropertiesIsNull() {
    InternalCacheBuilder internalCacheBuilder = new InternalCacheBuilder(
        null, new CacheConfig(), metricsSessionBuilder, THROWING_SYSTEM_SUPPLIER,
        constructorOf(constructedSystem()),
        THROWING_CACHE_SUPPLIER, constructorOf(constructedCache()));

    assertThatThrownBy(internalCacheBuilder::create)
        .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