@Test
    public void testSetProperties() {
        String[] values = null;
        Metadata meta = new Metadata();
        Properties props = new Properties();

        meta.setAll(props);
        assertEquals(0, meta.size());

        props.setProperty("name-one", "value1.1");
        meta.setAll(props);
        assertEquals(1, meta.size());
        values = meta.getValues("name-one");
        assertEquals(1, values.length);
        assertEquals("value1.1", values[0]);

        props.setProperty("name-two", "value2.1");
        meta.setAll(props);
        assertEquals(2, meta.size());
        values = meta.getValues("name-one");
        assertEquals(1, values.length);
        assertEquals("value1.1", values[0]);
        values = meta.getValues("name-two");
        assertEquals(1, values.length);
        assertEquals("value2.1", values[0]);
    }
Test for <code>setAll(Properties)</code> method.
tika-core/src/test/java/org/apache/tika/metadata/TestMetadata.java