@Test
    public void testToStringWithManyEntries() {
        Metadata m = new Metadata();
        m.add("key", "value1");
        m.add("key", "value2");
        m.add("key2", "value12");
        String metadata = m.toString();
        assertContains("key=value1", metadata);
        assertContains("key=value2", metadata);
        assertContains("key2=value12", metadata);
    }
Defines a composite property, then checks that when set as the
composite the value can be retrieved with the property or the aliases
tika-core/src/test/java/org/apache/tika/metadata/TestMetadata.java