updatecheck demo - DO NOT COMMIT

[decibel]

This is a demonstration of a working updatecheck target.

That target works by pulling down UPGRADE_FROM version of pgtap via pgxn (currently defaults to 0.94.0), installing the current version, and then doing

CREATE EXTENSION pgtap VERSION :'UPGRADE_FROM';
ALTER EXTENSION pgtap UPDATE :'CURRENT_VERSION';

then running the unit tests.

The other big change in here is that all installcheck activity is now managed with pg_regress execution schedules. There are two big wins from that:

• The extension is now loaded only once, not for every test
• Tests are now run in parallel by default (specify PARALLEL_CONN=1 to force serial)

To support that, there's now a test/build directory where temporary build objects are put.

If we're happy with this code then I'll get it into master and start hammering out the remaining upgrade issues.

[theory]

Why is this deleted; it's a generated file. Unless you mean to put it into test/.gitignore?

[decibel]

Where is it generated at? There's no target in the Makefile for it...

[theory]

Oh, I guess I switched to a static file in b8c7cb2 but neglected to remove it from .gitignore. So it's not generated anymore!

[nasbyj]

Testing of extension update was merged in #128.