@Test
public void testLog_timeAndMessage() {

    Span result = undertest.log(100L, "my message");
    assertSame(result, undertest);
    assertEquals(1, grpcSpan.getLogsCount());
    Log logRecord = grpcSpan.getLogs(0);
    Map<String, String> fieldMap = getLogFieldMap(logRecord);
    assertEquals("my message", fieldMap.get("message"));
    assertNull(fieldMap.get("payload"));
    assertEquals(100L, Util.protoTimeToEpochMicros(logRecord.getTimestamp()));
}