[ZEPPELIN-484] A small utility to help review the pullrequest.

[Leemoonsoo]

This PR address https://issues.apache.org/jira/browse/ZEPPELIN-484.

We've got discussions recently about impasse of pullrequest and speeding up of accepting pullrequest.
This small utility can be used when reviewer want to test the pullrequest.

Usage is

dev/test.py [#PR]

for example

dev/test.py 500

will create local branch pr500 and add remote repository of contribution, fetch and merge it for the test.

This script will help reduce small bit of time of reviewing.

[r-kamath]

@Leemoonsoo I do curl https://patch-diff.githubusercontent.com/raw/apache/incubator-zeppelin/pull/<PR#>.patch | git apply in master, review it and reset!

[prabhjyotsingh]

@r-kamath solution looks simpler, both are hacky though 😃

[jongyoul]

I've tested. Looks good. It's enough to me to test pr. Thanks.

[corneadoug]

Should we also include some:
git clean -dxf and then launch build then?

[bzz]

Looks great to me.

Another way to do the same is a small hub github/hub that allows you to do, apart from many other useful things, PR checkouts like

hub checkout https://github.com/apache/incubator-zeppelin/pull/513

It takes care of setting up a remote (so you can always pull from it later) and checking out a PR branch to your local repo.

[bzz]

@Leemoonsoo If we want to go further with this tool, as we already have ./dev/merge_zeppelin_pr.py may be we could name it something like ./dev/test_zeppelin_pr.py?

I feel that this, as well as a couple of lines of text comments in the header after the licence boilerplate, will give a better idea of it's purpose for people who will just notice it in the filesystem, what do you think?

[Leemoonsoo]

Thanks all the feedbacks and alternative solutions.

I have changed script name from test.py to test_zeppelin_pr.py and add more comment.
Adding git clean -dxf will remove untracked files. I think it's better leave it up to developers.

[bzz]

Looks great to me

[Leemoonsoo]

merging into master