### Question:
MetadataIdentificationUtils { public static String getMetadataClass(final String metadataId) { if (!isValid(metadataId) || metadataId.equals(MID_PREFIX + INSTANCE_DELIMITER)) { return null; } final int delimiterIndex = metadataId.indexOf(INSTANCE_DELIMITER); if (delimiterIndex == -1) { return metadataId.substring(MID_PREFIX_LENGTH); } return metadataId.substring(MID_PREFIX_LENGTH, delimiterIndex); } private  MetadataIdentificationUtils(); static String create(final Class<?> metadataClass); static String create(final String fullyQualifiedClassName); static String create(final String fullyQualifiedMetadataClass,
      final String instanceIdentificationKey); static String getMetadataClass(final String metadataId); static String getMetadataClassId(final String metadataId); static String getMetadataInstance(final String metadataId); static boolean isIdentifyingClass(final String metadataIdentificationString); static boolean isIdentifyingInstance(final String metadataIdentificationString); static boolean isValid(final String metadataIdentificationString);  }### Answer:
@Test public void testGetMetadataClassFromClassMid() { assertEquals(METADATA_CLASS, MetadataIdentificationUtils.getMetadataClass(CLASS_MID)); }
@Test public void testGetMetadataClassFromEmptyMid() { assertNull(MetadataIdentificationUtils.getMetadataClass("")); }
@Test public void testGetMetadataClassFromInstanceMid() { assertEquals(METADATA_CLASS, MetadataIdentificationUtils.getMetadataClass(INSTANCE_MID)); }
@Test public void testGetMetadataClassFromMidPrefix() { assertNull(MetadataIdentificationUtils.getMetadataClass(MID_PREFIX)); }
@Test public void testGetMetadataClassFromMidPrefixPlusDelimiter() { assertNull(MetadataIdentificationUtils.getMetadataClass(MID_PREFIX + INSTANCE_DELIMITER)); }
@Test public void testGetMetadataClassFromNullMid() { assertNull(MetadataIdentificationUtils.getMetadataClass(null)); }