StringTag extends AbstractTag<String> { @Override public void set(Span span, String tagValue) { span.setTag(super.key, tagValue); } StringTag(String key); @Override void set(Span span, String tagValue);  }
@Test public void testSetString() { String value = "expected.value"; String key = "expected.key"; Span span = mock(Span.class); StringTag tag = new StringTag(key); tag.set(span, value); verify(span).setTag(key, value); }