duplicate tests
tests.indexes.datetimes.test_ops.TestDateTimeIndexToJulianDate
tests.indexes.datetimes.test_misc.TestDateTimeIndexToJulianDate

Will update if/when I find others.

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https://github.com/pandas-dev/pandas/blob/master/pandas/tests/indexes/timedeltas/test_timedelta.py#L578
TestSlicing has one method `test_timedelta` and it isn't clear it has anything to do with slicing.

https://github.com/pandas-dev/pandas/blob/master/pandas/tests/indexes/timedeltas/test_ops.py#L1214
test_ops.TestSlicing.test_tdi_ops_attributes doesnt appear to have anything to do with slicing

https://github.com/pandas-dev/pandas/blob/master/pandas/tests/indexes/timedeltas/test_ops.py#L1250
test_ops.TestSlicing.test_add_overflow appears arithmetic based.  In fact it _almost_ catches one of the errors in #18020.