@Test
public void testSetTag_stringTypeNullValue() {

    Span result = undertest.setTag("k", (String) null);
    assertSame(result, undertest);
    verify(abstractTracer).debug("key (k) or value (null) is null, ignoring");
    assertTrue("When value is null, should not be added to attributes", grpcSpan.getTagsList().isEmpty());
}