use following markup to create a test page in ace chart (QA test). NOte that the ace:printer does not display any of the actual chart data (just the grids, legends, etc). If you use File->Print from the browser the bar chart data does display.

<h:form id="renderedForm">
<ace:panel id="panOutput" header="selectedChart" rendered="#{not empty barChart.barData}">
<ace:chart id="chart" stackedSeries="false"
                       animated="false"
                       xAxis="#{barChart.xAxis}"
                       yAxes="#{barChart.yAxes}"
                       widgetVar="barChart1"
                       value="#{barChart.barData}" />
        </ace:panel>
        <ace:panel id="prChoose" >
            <h:commandLink id="prchart">
                <h:outputText id="p1" value="Print Chart"/>
                <ace:printer for="panOutput"/>
            </h:commandLink>
        </ace:panel>
</h:form>