Running Standalone TAP Tests

Recent discussion set me thinking about what would be involved in setting up standalone TAP tests for Postgres, to do, say, more code coverage than we get from the current core tests. So I started experimenting. And with a tiny bit of Makefile magic it turns out to be absurdly easy.

You need just two things: an entirely boilerplate Makefile and a tiny bit of glue at the top of your TAP test files.

First let's look at the Makefile. Here it is in its entirety:

TAP_TESTS = 1

PG_CONFIG = pg_config
PGXS := $(shell $(PG_CONFIG) --pgxs)
include $(PGXS)

# install_path for PostgreSQL binaries etc
PG_INSTALL_ROOT := $(dir $(shell $(PG_CONFIG) --bindir))
export PG_INSTALL_ROOT

# where to find PostgresNode and friends
PG_NODE_LOC = $(top_srcdir)/src/test/perl
export PG_NODE_LOC

Then in your TAP test perl file(s) (which should reside in a subdirectory called "t") you put this:

use lib "$ENV{PG_NODE_LOC}";

use PostgresNode;
use Test::More;

local $ENV{PG_REGRESS} = "/bin/true";

my $node_inst = $ENV{PG_INSTALL_ROOT};

# for pre--release-14 releases you would possibly set LD_LIBRARY_PATH
# based on this. For release 14 and up PostgresNode does that for you
# via the install_path parameter.

my $node = PostgresNode->get_new_node('dummy', install_path => $node_inst);

...

That's all you need. Given that you can run your TAP tests with just a Postgres installation, as in this example:

andrew@emma:tests $ make PG_CONFIG=../inst.head.5701/bin/pg_config installcheck
rm -rf '/home/andrew/pgl/tests'/tmp_check
/usr/bin/mkdir -p '/home/andrew/pgl/tests'/tmp_check
cd ./ && TESTDIR='/home/andrew/pgl/tests' PATH="/home/andrew/pgl/inst.head.5701/bin:$PATH" PGPORT='65701' \
  top_builddir='/home/andrew/pgl/tests//home/andrew/pgl/inst.head.5701/lib/postgresql/pgxs/src/makefiles/../..' \
  PG_REGRESS='/home/andrew/pgl/tests//home/andrew/pgl/inst.head.5701/lib/postgresql/pgxs/src/makefiles/../../src/test/regress/pg_regress' \
  REGRESS_SHLIB='/src/test/regress/regress.so' \
  /usr/bin/prove -I /home/andrew/pgl/inst.head.5701/lib/postgresql/pgxs/src/makefiles/../../src/test/perl/ -I ./  t/*.pl
t/dummy.pl .. ok   
All tests successful.
Files=1, Tests=1,  3 wallclock secs ( 0.04 usr  0.01 sys +  1.22 cusr  0.36 csys =  1.63 CPU)
Result: PASS

The Makefile and a demo TAP test are at This Gitlab repo

In the next episode, we'll look at how to leverage this so that your standalone tests are run by your buildfarm animal.

Buildfarm adopts modern git naming

In keeping with modern git practice, I have renamed the default branch on both the client-code and server-code repositories to main. If you have a clone of either of these repositories, you can adapt to the change by doing the following commands in your local repo:

git checkout master
git branch -m main
git fetch
git branch --unset-upstream
git branch -u origin/main
git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main
git fetch -p

There is still a bunch of work to do to ensure that things run smoothly when source repositories such as The PostgreSQL Git repository make this change, as will surely happen at some stage. I will be testing this on a small source repository I control - the plan is that when it happens it will be transparent to buildfarm animals.

 Update (August 4 2021):

I just went to update a couple of machines with very old versions of git. They choked on these lines

git branch --unset-upstream
git branch -u origin/main

The solution is instead to edit the .git/config file directly. In these lines change "master" to "main":

[branch "main"]
    remote = origin
    merge = refs/heads/master

The rest of the recipe worked fine. In some cases you might need a final git pull.