Add minimal CI. (#61)

This is a basic github action setup.  It's currently executed only on the
master branch and PRs against it.  It's run against all currrent postgres major
versions on ubuntu 22.04.  Note that the list of major versions and the OS
version are hardcoded and have to be maintained.

Adapted from powa-archivist.

.github/workflows/tests.yml

@@ -0,0 +1,97 @@
+name: Run pg_qualstats tests
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+env:
+  DATADIR: /dev/shm/data
+  LOGFILE: /dev/shm/data/logfile
+
+jobs:
+  pg_qualstats_tests:
+    name: pg_qualstats tests
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        postgres_major_version: [
+          "12",
+          "13",
+          "14",
+          "15",
+          "16"
+        ]
+        os: ["ubuntu-22.04"]
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Set up prerequisites and environment
+      run: |
+        echo "************ CLEAN IMAGE ***********"
+        sudo apt remove -y '^postgres.*' '^libpq.*'
+        echo ""
+
+        echo "********* REPOSITORY SET UP ********"
+        sudo apt-get install -y wget gnupg
+        sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'
+        wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
+        sudo apt-get update -y -qq --fix-missing
+        echo ""
+
+        echo "*********** ENVIRONMENT ************"
+        export PG_MAJOR_VERSION=${{ matrix.postgres_major_version }}
+        echo "PG_MAJOR_VERSION=$PG_MAJOR_VERSION" >> $GITHUB_ENV
+        echo "MAKEFLAGS=$MAKEFLAGS -j $(grep -c ^processor /proc/cpuinfo)" >> $GITHUB_ENV
+        echo ""
+
+        echo "******** INSTALL POSTGRES **********"
+        sudo apt-get install -y \
+          postgresql-$PG_MAJOR_VERSION \
+          postgresql-server-dev-$PG_MAJOR_VERSION \
+          postgresql-contrib-$PG_MAJOR_VERSION
+        echo ""
+
+        echo "******* INSTALL DEPENDENCIES *******"
+        sudo apt-get install -y \
+          gcc \
+          make \
+          build-essential \
+          pkg-config
+        echo ""
+
+        echo "********** READJUST PATH ***********"
+        export PATH=$(pg_config --bindir):$PATH
+        echo "PATH=$PATH" >> $GITHUB_ENV
+        cat $GITHUB_ENV
+        echo ""
+
+    - name: Start a postgres ${{ matrix.postgres_major_version }} server
+      run: |
+        sudo chmod a+rwx /var/run/postgresql/
+        pg_ctl -D $DATADIR initdb
+        echo "shared_preload_libraries = 'pg_stat_statements'" >> $DATADIR/postgresql.conf
+        pg_ctl -D $DATADIR -l $LOGFILE start || cat $LOGFILE
+        psql -c 'select 1 as ok' postgres
+
+    - name: Build and install pg_qualstats for postgres ${{ matrix.postgres_major_version }}
+      run: |
+        make
+        sudo make install
+
+    - name: Enable pg_qualstats on postgres ${{ matrix.postgres_major_version }} server
+      run: |
+        echo "shared_preload_libraries = 'pg_stat_statements,pg_qualstats'" >> $DATADIR/postgresql.conf
+        pg_ctl -D $DATADIR -l $LOGFILE restart || cat $LOGFILE
+        psql -c 'select 1 as ok' postgres
+
+    - name: Run pg_qualstats tests for postgres ${{ matrix.postgres_major_version }}
+      run: make installcheck || ( errcode=$?; cat regression.diffs && exit $errcode )
+
+    - name: Stop the running postgres ${{ matrix.postgres_major_version }} server
+      run: pg_ctl -D $DATADIR stop