### Question:
MultiConfigurationValueProvider implements IConfigurationValueProvider, ICloneable <MultiConfigurationValueProvider> { @Nullable public ConfiguredValue getConfigurationValue (@Nonnull @Nonempty final String sKey) { ConfiguredValue ret = null; for (final CS aSource : m_aSources) { ret = aSource.m_aCVP.getConfigurationValue (sKey); if (ret != null) { break; } } return ret; } MultiConfigurationValueProvider();  MultiConfigurationValueProvider(@Nullable final List <? extends IConfigurationSource> aSources);  MultiConfigurationValueProvider(@Nullable final IConfigurationSource... aSources); final boolean isUseOnlyInitializedConfigSources(); @Nonnull final MultiConfigurationValueProvider setUseOnlyInitializedConfigSources(final boolean bUseOnlyInitializedConfigSources); @Nonnull final MultiConfigurationValueProvider addConfigurationSource(@Nonnull final IConfigurationSource aSource); @Nonnull final MultiConfigurationValueProvider addConfigurationSource(@Nullable final IConfigurationValueProvider aCVP,
                                                                       final int nPriority); @Nonnegative final int getConfigurationSourceCount(); @Nullable ConfiguredValue getConfigurationValue(@Nonnull @Nonempty final String sKey); void forEachConfigurationValueProvider(@Nonnull final IConfigurationValueProviderWithPriorityCallback aCallback); @Nonnull @ReturnsMutableCopy MultiConfigurationValueProvider getClone(); @Nullable static MultiConfigurationValueProvider createForClassPath(@Nonnull final ClassLoader aClassLoader,
                                                                    @Nonnull final String sClassPathElement,
                                                                    @Nonnull final Function <URL, IConfigurationSource> aLoader); @Nullable static MultiConfigurationValueProvider createForAllOccurrances(@Nonnull final ClassLoader aClassLoader,
                                                                         @Nonnull final String sPathName,
                                                                         @Nonnull final Function <URL, IConfigurationSource> aLoader,
                                                                         final boolean bCheckForFile); static final boolean DEFAULT_USE_ONLY_INTIIALIZED_CONFIG_SOURCES; }### Answer:
@Test public void testEmpty () { final MultiConfigurationValueProvider aMCSVP = new MultiConfigurationValueProvider (); assertNull (aMCSVP.getConfigurationValue ("key1")); assertNull (aMCSVP.getConfigurationValue ("key2")); assertNull (aMCSVP.getConfigurationValue ("key3")); assertNull (aMCSVP.getConfigurationValue ("key4")); }