### Question:
SchemaSource { @Override public String toString() { return source.getSystemId().toString(); } SchemaSource(final InputStream inputStream, final String systemId); Source getSource(); @Override String toString(); @Override int hashCode(); @Override boolean equals(final Object obj);  }### Answer:
@Test public void testToString() { final String toString = schemaSource.toString(); assertNotNull("String from the schema source is null.", toString); assertEquals("Unexpected value of schema source's string.", SYSTEM_ID, toString); }