ci: align test matrix with redmine_gtt

Adds the postgis 17-3.5 cell and the system-test include (6.1-stable +
Ruby 3.4) so both plugins run the same matrix. The system suite is
skipped until test/system exists.

Author: dkastl

.github/workflows/test-postgis.yml

@@ -27,8 +27,13 @@ jobs:
         #   6.1-stable -> 3.3, 3.4
         redmine_version: [6.0-stable, 6.1-stable]
         ruby_version: ['3.3', '3.4']
-        # postgis/postgis tags spanning PG 15/17/18 and PostGIS 3.4/3.5/3.6.
-        db_version: [15-3.4, 18-3.6]
+        # postgis/postgis tags spanning PG 15/17/18 and PostGIS 3.4/3.5/3.6
+        # (floor -> ceiling), matching the redmine_gtt matrix.
+        db_version: [15-3.4, 17-3.5, 18-3.6]
+        include:
+          - system_test: true
+            redmine_version: 6.1-stable
+            ruby_version: '3.4'
         exclude:
           # Redmine 6.0 supports Ruby up to 3.3 only.
           - redmine_version: 6.0-stable
@@ -117,12 +122,19 @@ jobs:
       - name: Run tests
         env:
           RAILS_ENV: test
+          # For system tests in the plugin
+          GOOGLE_CHROME_OPTS_ARGS: "headless,disable-gpu,no-sandbox,disable-dev-shm-usage"
         working-directory: redmine
         # Only run suites that exist; `rails test` raises LoadError on a
-        # missing directory (functional/integration get added as Phase 0
-        # progresses).
+        # missing directory (functional/integration/system get added as the
+        # revival progresses). System tests only run on the designated matrix
+        # cell, like in redmine_gtt.
         run: |
-          for suite in unit functional integration; do
+          suites="unit functional integration"
+          if [ "${{ matrix.system_test }}" = "true" ]; then
+            suites="$suites system"
+          fi
+          for suite in $suites; do
             dir="plugins/${{ env.PLUGIN_NAME }}/test/$suite"
             if [ -d "$dir" ]; then
               bundle exec rails test "$dir"