CI/DOC: fix clipboard on travis
- [ ] closes #26075

this is more complex than what I thought. I will relook tomorrow.  # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=h1) Report
> Merging [#26103](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/b90f9db6d23f64b0ce9ff469445e1c31013a07c0?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26103/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26103      +/-   ##
==========================================
- Coverage   91.96%   91.95%   -0.01%     
==========================================
  Files         175      175              
  Lines       52405    52405              
==========================================
- Hits        48193    48189       -4     
- Misses       4212     4216       +4
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.51% <ø> (ø)` | :arrow_up: |
| #single | `40.72% <ø> (-0.14%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `75% <0%> (-12.5%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `96.9% <0%> (-0.12%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26103?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/26103?src=pr&el=footer). Last update [b90f9db...3b6b879](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=h1) Report
> Merging [#26103](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/9c5165e26260483ae64300c4d98939bf575aab7e?src=pr&el=desc) will **increase** coverage by `0.03%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/26103/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #26103      +/-   ##
==========================================
+ Coverage   91.69%   91.72%   +0.03%     
==========================================
  Files         174      174              
  Lines       50739    50741       +2     
==========================================
+ Hits        46523    46544      +21     
+ Misses       4216     4197      -19
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.23% <ø> (+0.03%)` | :arrow_up: |
| #single | `41.68% <ø> (+0.36%)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `78.94% <0%> (-10.53%)` | :arrow_down: |
| [pandas/core/frame.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZnJhbWUucHk=) | `97.02% <0%> (-0.12%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `90.7% <0%> (+0.1%)` | :arrow_up: |
| [pandas/core/generic.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ2VuZXJpYy5weQ==) | `93.49% <0%> (+0.14%)` | :arrow_up: |
| [pandas/io/clipboard/clipboards.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2NsaXBib2FyZC9jbGlwYm9hcmRzLnB5) | `31.64% <0%> (+12.65%)` | :arrow_up: |
| [pandas/io/clipboard/\_\_init\_\_.py](https://codecov.io/gh/pandas-dev/pandas/pull/26103/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2NsaXBib2FyZC9fX2luaXRfXy5weQ==) | `56.86% <0%> (+17.64%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/26103?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/26103?src=pr&el=footer). Last update [9c5165e...d8c6dc4](https://codecov.io/gh/pandas-dev/pandas/pull/26103?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 I am unable to replicate this in any of my environments. Thus I am create PRs to investigate.  @saurav2608 meaning the doc-build does not show any pyperclip error? closing as stale (reopened to try something out, based on the diff I noticed the use of `export DISPLAY`, and that it was in a different place before. Who knows that makes a difference ..) @jreback OK?

(if this passes, will add a comment explaining why / referencing this PR)  so these are actually run? can u show that somewhere
maybe should make these tests highly visible somehow What do you mean with "so these are actually run?" ? 
Or is it a comment meant for a different PR? (there are no tests involved here, only for doc building) @jorisvandenbossche we didn't notice that we should be running these (and weren't); I dont' think this has changed. We need a highly visible test that we can simply look in the logs and inspect (maybe just add a print statement to it).

https://travis-ci.org/pandas-dev/pandas/jobs/532738283

```
-----------------------------------------------------------------------------------------------------------------------------
#5 pandas.tests.test_algos.TestRank.test_pct_max_many_rows[1d]: skipping high memory test since --run-high-memory was not set
#6 pandas.tests.test_algos.TestRank.test_pct_max_many_rows[2d]: skipping high memory test since --run-high-memory was not set
------------------------------------------------------------------------------------------------------------------------------
#7 pandas.tests.frame.test_rank.TestRank.test_pct_max_many_rows: skipping high memory test since --run-high-memory was not set
-----------------------------------------------------------------------------------------------------------------
#8 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[delims]: clipboard primitives not installed
#9 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[utf8]: clipboard primitives not installed
#10 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[utf16]: clipboard primitives not installed
#11 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[string]: clipboard primitives not installed
#12 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[long]: clipboard primitives not installed
#13 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[nonascii]: clipboard primitives not installed
#14 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[colwidth]: clipboard primitives not installed
#15 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[mixed]: clipboard primitives not installed
#16 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[float]: clipboard primitives not installed
#17 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame[int]: clipboard primitives not installed
#18 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[delims-\t]: clipboard primitives not installed
#19 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[delims-,]: clipboard primitives not installed
#20 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[delims-|]: clipboard primitives not installed
#21 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[utf8-\t]: clipboard primitives not installed
#22 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[utf8-,]: clipboard primitives not installed
#23 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[utf8-|]: clipboard primitives not installed
#24 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[utf16-\t]: clipboard primitives not installed
#25 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[utf16-,]: clipboard primitives not installed
#26 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[utf16-|]: clipboard primitives not installed
#27 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[string-\t]: clipboard primitives not installed
#28 pandas.tests.io.test_clipboard.TestClipboard.test_round_trip_frame_sep[string-,]: clipboard primitives not installed
``` Ah, so those tests have not been running on master for a while? (since the CI env refactor PR https://github.com/pandas-dev/pandas/pull/24632), ok, I see now.

But it seems that this PR actually solves that. They are running again (just not on the first travis build, but if you look eg at the second travis build: https://travis-ci.org/pandas-dev/pandas/jobs/532738284: no message about skipped tests anymore. On the first travis build, they have been skipped even before the CI env refactor). 

But not sure I understand why the first travis build (in the build matrix) would skip those and the second not. I don't see anything in their definition that can explain that (the clipboard tests are marked as 'single'). > But not sure I understand why the first travis build (in the build matrix) would skip those and the second not.

Ah, maybe because the first build has no qt installed and the second does (through matplotlib), travis-37.yml vs travis-36-locale.yaml. right I don't care that they run on *all* builds, but at least one. I think just add a print statement in the basic clip test might be enough here to provide us an easy visual reference. @jreback I added some print statements, but they don't show up in the travis logs (although we have `-s` in the pytest command) @jorisvandenbossche then how can we be sure these are actually run? This is the entire problem. Well, you can say that for all other tests as well... 
Unless we do `-v` to show each test that has been run. > Well, you can say that for all other tests as well...
Unless we do -v to show each test that has been run.

maybe, but this is a continual issue, and we need a foolproof way to say these tests are actually run Will open an issue about that, but merging this since it is actually solving a problem @saurav2608 thanks for putting me on the right track with the DISPLAY change ! > @saurav2608 thanks for putting me on the right track with the DISPLAY change !

@jorisvandenbossche  Absolutely. I wish I could have contributed more.  I am totally swamped at work. 