Dynamically generate matrix

.github/workflows/test.yml

@@ -17,41 +17,52 @@ on:
   workflow_dispatch:  
 
 jobs:
-  test:
+  generate-matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.generate-matrix.outputs.value }}
+    steps:
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.3'
+      - id: generate-matrix
+        run: |
+          cat <<EOS | ruby >> $GITHUB_OUTPUT
+            require 'json'
+          
+            # In order to effectively specify Rails and Ruby versions simultaneously,
+            # we test only the oldest and latest Ruby versions for each Rails version.
+            rubies_by_gemfile = {
+              'gemfiles/rails_5.gemfile' => ['2.3', '2.6'],
+              'gemfiles/rails_6.0.gemfile' => ['2.5', '2.7'],
+              'gemfiles/rails_6.1.gemfile' => ['2.5', '3.2'],
+              'gemfiles/rails_7.0.gemfile' => ['2.7', '3.2'],
+            }
+            adapters = ['trilogy', 'mysql2']
+
+            matrix = JSON.generate(
+              adapters.flat_map do |adapter|
+                rubies_by_gemfile.flat_map do |gemfile, rubies|
+                  rubies.map do |ruby|
+                    { ruby: ruby, gemfile: gemfile, adapter: adapter }
+                  end
+                end
+              end
+            )
 
+            puts "value=#{matrix}"
+          EOS
+
+  test:
+    needs: generate-matrix
     runs-on: ubuntu-latest
-
     strategy:
       max-parallel: 4
       fail-fast: true
       matrix:
-        # In order to effectively specify Rails and Ruby versions simultaneously,
-        # we specify every tuple of versions in `include` section
-        # except for the tuples with a particular Rails version.
-        #
-        # The objective of the exception is to satisfy the
-        # constraint that a matrix cannot be empty.
-        #
-        # We test only the oldest and latest Ruby versions for each Rails version.
-        gemfile: [gemfiles/rails_5.gemfile]
-        ruby: ['2.3', '2.6']
-        adapter: ['trilogy', 'mysql2']
-        include:
-          - gemfile: gemfiles/rails_6.0.gemfile
-            ruby: '2.5'
-          - gemfile: gemfiles/rails_6.0.gemfile
-            ruby: '2.7'
-          - gemfile: gemfiles/rails_6.1.gemfile
-            ruby: '2.5'
-          - gemfile: gemfiles/rails_6.1.gemfile
-            ruby: '3.2'
-          - gemfile: gemfiles/rails_7.0.gemfile
-            ruby: '2.7'
-          - gemfile: gemfiles/rails_7.0.gemfile
-            ruby: '3.2'
-
+        spec: ${{ fromJson(needs.generate-matrix.outputs.matrix) }}
     env:
-      BUNDLE_GEMFILE: ${{ matrix.gemfile }}
+      BUNDLE_GEMFILE: ${{ matrix.spec.gemfile }}
     services:
       mysql:
         image: iwata/centos6-mysql56-q4m-hs
@@ -66,10 +77,10 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         bundler-cache: true
-        ruby-version: ${{ matrix.ruby }}
+        ruby-version: ${{ matrix.spec.ruby }}
     - name: Install dependencies
       run: bundle install
     - name: Run tests
       env:
-        SHINQ_TEST_ADAPTER: ${{ matrix.adapter }}
+        SHINQ_TEST_ADAPTER: ${{ matrix.spec.adapter }}
       run: bundle exec rspec