    @Test
    public void testLabelFromBaggage() {

        MetricLabel label = new BaggageMetricLabel(TEST_LABEL, TEST_LABEL_DEFAULT);
        SpanData spanData = mock(SpanData.class);
        when(spanData.getBaggageItem(anyString())).thenReturn("BaggageValue");
        
        assertEquals("BaggageValue", label.value(spanData));
        verify(spanData, times(1)).getBaggageItem(TEST_LABEL);
    }