Update postgresql testing script

changelog.d/10906.misc

@@ -0,0 +1 @@
+Update development testing script `test_postgresql.sh` to use a support Python version and make re-runs quicker.

docker/Dockerfile-pgtests

@@ -1,12 +1,21 @@
 # Use the Sytest image that comes with a lot of the build dependencies
 # pre-installed
-FROM matrixdotorg/sytest:latest
+FROM matrixdotorg/sytest:bionic
 
 # The Sytest image doesn't come with python, so install that
 RUN apt-get update && apt-get -qq install -y python3 python3-dev python3-pip
 
 # We need tox to run the tests in run_pg_tests.sh
 RUN python3 -m pip install tox
 
+# Initialise the db
+RUN su -c '/usr/lib/postgresql/10/bin/initdb -D /var/lib/postgresql/data -E "UTF-8" --lc-collate="en_US.UTF-8" --lc-ctype="en_US.UTF-8" --username=postgres' postgres
+
+# Create a volume for tox's workdir (so we don't have to fetch dependencies from PyPI every run)
+VOLUME /tox
+
 ADD run_pg_tests.sh /pg_tests.sh
-ENTRYPOINT /pg_tests.sh
+
+# Use the "exec form" of ENTRYPOINT (https://docs.docker.com/engine/reference/builder/#entrypoint)
+# so that we can `docker run` this container and pass arguments to pg_tests.sh
+ENTRYPOINT ["/pg_tests.sh"]

docker/run_pg_tests.sh

@@ -10,11 +10,10 @@ set -e
 # Set PGUSER so Synapse's tests know what user to connect to the database with
 export PGUSER=postgres
 
-# Initialise & start the database
-su -c '/usr/lib/postgresql/9.6/bin/initdb -D /var/lib/postgresql/data -E "UTF-8" --lc-collate="en_US.UTF-8" --lc-ctype="en_US.UTF-8" --username=postgres' postgres
-su -c '/usr/lib/postgresql/9.6/bin/pg_ctl -w -D /var/lib/postgresql/data start' postgres
+# Start the database
+su -c '/usr/lib/postgresql/10/bin/pg_ctl -w -D /var/lib/postgresql/data start' postgres
 
 # Run the tests
 cd /src
 export TRIAL_FLAGS="-j 4"
-tox --workdir=/tmp -e py35-postgres
+tox --workdir=/tox -e py36-postgres "$@"

scripts-dev/test_postgresql.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# This script builds the Docker image to run the PostgreSQL tests, and then runs
+# the tests. It uses a dedicated tox environment so that we don't have to
+# rebuild it each time.
+
+# Command line arguments to this script are forwarded to "tox" and then to "trial".
+
+set -e
+
+# Build, and tag
+docker build docker/ -f docker/Dockerfile-pgtests -t synapsepgtests
+
+# Create a place to persist tox's environment so reruns are faster.
+# NB: I'm using a separate docker volume here, because you may have already run
+# "tox -e py36-postgres" on your system. You might not be using the distro used
+# in Dockerfile-pgtests, and so might be using a different CPython build! I don't
+# want there to be any accidental clashes
+docker volume create synapse-pg-test-tox
+
+# Run, mounting the current directory into /src
+docker run --rm -it -v "$(pwd):/src" -v synapse-pg-test-tox:/tox synapsepgtests "$@"