@Test
  public void testGetDefaultStreamProperties() {
    String defaultStreamPrefix = buildDefaultStreamPropertiesPrefix(MOCK_SYSTEM_NAME1);
    String system1ConfigKey = "config1-key";
    String system1ConfigValue = "config1-value";
    String system2ConfigKey = "config2-key";
    String system2ConfigValue = "config2-value";

    Config config = new MapConfig(ImmutableMap.of(defaultStreamPrefix + system1ConfigKey, system1ConfigValue,
        defaultStreamPrefix + system2ConfigKey, system2ConfigValue));
    Config expected =
        new MapConfig(ImmutableMap.of(system1ConfigKey, system1ConfigValue, system2ConfigKey, system2ConfigValue));
    SystemConfig systemConfig = new SystemConfig(config);
    assertEquals(expected, systemConfig.getDefaultStreamProperties(MOCK_SYSTEM_NAME1));
    assertEquals(new MapConfig(), systemConfig.getDefaultStreamProperties(MOCK_SYSTEM_NAME2));
  }
Placeholder to help make sure the correct {@link SystemAdmin} is returned by {@link MockSystemFactory}. Do not mock
any methods of this mock.
samza-core/src/test/java/org/apache/samza/config/TestSystemConfig.java