    @Test
    // Tests Source\tDest\tVertexValue\tEdgeValue
    public void testWriteGraphAsEdgesAndVertexValuesAndOverriddenDelimiter() throws Exception {

        TextEdgeWriter<Text, Text, Text> writer = createEdgeWriter(rw);
        conf.set(WRITE_EDGE_VALUE, "true");
        conf.set(WRITE_VERTEX_VALUE, "true");
        conf.set(FIELD_DELIMITER, "\t");
        writer.setConf(conf);
        writer.initialize(tac);
        writer.writeEdge(vertex.getId(), vertex.getValue(), edge1);
        verify(rw).write(new Text("34\t12\t10\t1"), null);
        writer.writeEdge(vertex.getId(), vertex.getValue(), edge2);
        verify(rw).write(new Text("34\t6\t10\t4"), null);
    }