326       {absl::FromUnixSeconds(1) + absl::Microseconds(1), {1, 1}},  in TEST()
327       {absl::FromUnixSeconds(1) + absl::Microseconds(1) / 2, {1, 0}},  in TEST()
328       {absl::FromUnixSeconds(1) + absl::Microseconds(0), {1, 0}},  in TEST()
329       {absl::FromUnixSeconds(0) + absl::Microseconds(0), {0, 0}},  in TEST()
330       {absl::FromUnixSeconds(0) - absl::Microseconds(1) / 2, {-1, 999999}},  in TEST()
331       {absl::FromUnixSeconds(0) - absl::Microseconds(1), {-1, 999999}},  in TEST()
332       {absl::FromUnixSeconds(-1) + absl::Microseconds(1), {-1, 1}},  in TEST()
333       {absl::FromUnixSeconds(-1) + absl::Microseconds(1) / 2, {-1, 0}},  in TEST()
334       {absl::FromUnixSeconds(-1) + absl::Microseconds(0), {-1, 0}},  in TEST()
335       {absl::FromUnixSeconds(-1) - absl::Microseconds(1) / 2, {-2, 999999}},  in TEST()
344       {{1, 1}, absl::FromUnixSeconds(1) + absl::Microseconds(1)},  in TEST()
345       {{1, 0}, absl::FromUnixSeconds(1) + absl::Microseconds(0)},  in TEST()
346       {{0, 0}, absl::FromUnixSeconds(0) + absl::Microseconds(0)},  in TEST()
347       {{0, -1}, absl::FromUnixSeconds(0) - absl::Microseconds(1)},  in TEST()
348       {{-1, 999999}, absl::FromUnixSeconds(0) - absl::Microseconds(1)},  in TEST()
349       {{-1, 1}, absl::FromUnixSeconds(-1) + absl::Microseconds(1)},  in TEST()
350       {{-1, 0}, absl::FromUnixSeconds(-1) + absl::Microseconds(0)},  in TEST()
351       {{-1, -1}, absl::FromUnixSeconds(-1) - absl::Microseconds(1)},  in TEST()
352       {{-2, 999999}, absl::FromUnixSeconds(-1) - absl::Microseconds(1)},  in TEST()
990   t += absl::Microseconds(1);  in TEST()
994   t += absl::Microseconds(1);  // no effect  in TEST()
1005   t -= absl::Microseconds(1);  in TEST()
1009   t -= absl::Microseconds(1);  // no effect  in TEST()