Tests for TDI issues already fixed
Fix a couple others caused by failing to return NotImplemented or to override names correctly.

closes #17250
xref #19042 
closes #19043
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

  
  
  
@jbrockmendel : Triple threat PR, very nice! :+1:  # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19044?src=pr&el=h1) Report
> :exclamation: No coverage uploaded for pull request base (`master@856c92b`). [Click here to learn what that means](https://docs.codecov.io/docs/error-reference#section-missing-base-commit).
> The diff coverage is `83.33%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/19044/graphs/tree.svg?token=eZ4WkYLtcO&height=150&src=pr&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/19044?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##             master   #19044   +/-   ##
=========================================
  Coverage          ?   91.53%           
=========================================
  Files             ?      148           
  Lines             ?    48691           
  Branches          ?        0           
=========================================
  Hits              ?    44569           
  Misses            ?     4122           
  Partials          ?        0
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.9% <83.33%> (?)` | |
| #single | `41.62% <66.66%> (?)` | |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/19044?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/ops.py](https://codecov.io/gh/pandas-dev/pandas/pull/19044/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvb3BzLnB5) | `91.89% <100%> (ø)` | |
| [pandas/core/indexes/timedeltas.py](https://codecov.io/gh/pandas-dev/pandas/pull/19044/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy90aW1lZGVsdGFzLnB5) | `90.92% <50%> (ø)` | |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19044?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/19044?src=pr&el=footer). Last update [856c92b...10296e8](https://codecov.io/gh/pandas-dev/pandas/pull/19044?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 Hello @jbrockmendel! Thanks for updating the PR.







Cheers ! There are no PEP8 issues in this Pull Request. :beers: 

##### Comment last updated on January 05, 2018 at 16:45 Hours UTC rebase and lgtm. ping thanks @jbrockmendel 