Improve startup times in Complement test runs against workers, particularly in CPU-constrained environments. (#13127)

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

.github/workflows/tests.yml

@@ -328,51 +328,8 @@ jobs:
           - arrangement: monolith
             database: Postgres
 
-    steps:
-      # The path is set via a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on the path to run Complement.
-      # See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
-      - name: "Set Go Version"
-        run: |
-          # Add Go 1.17 to the PATH: see https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-Readme.md#environment-variables-2
-          echo "$GOROOT_1_17_X64/bin" >> $GITHUB_PATH
-          # Add the Go path to the PATH: We need this so we can call gotestfmt
-          echo "~/go/bin" >> $GITHUB_PATH
-
-      - name: "Install Complement Dependencies"
-        run: |
-          sudo apt-get update && sudo apt-get install -y libolm3 libolm-dev
-          go get -v github.com/haveyoudebuggedit/gotestfmt/v2/cmd/gotestfmt@latest
-
-      - name: Run actions/checkout@v2 for synapse
-        uses: actions/checkout@v2
-        with:
-          path: synapse
-
-      - name: "Install custom gotestfmt template"
-        run: |
-          mkdir .gotestfmt/github -p
-          cp synapse/.ci/complement_package.gotpl .gotestfmt/github/package.gotpl
-
-      # Attempt to check out the same branch of Complement as the PR. If it
-      # doesn't exist, fallback to HEAD.
-      - name: Checkout complement
-        run: synapse/.ci/scripts/checkout_complement.sh
-
-      - run: |
-          set -o pipefail
-          POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
-        shell: bash
-        name: Run Complement Tests
-
-  # We only run the workers tests on `develop` for now, because they're too slow to wait for on PRs.
-  # Sadly, you can't have an `if` condition on the value of a matrix, so this is a temporary, separate job for now.
-  # GitHub Actions doesn't support YAML anchors, so it's full-on duplication for now.
-  complement-developonly:
-    if: "${{ !failure() && !cancelled() && (github.ref == 'refs/heads/develop') }}"
-    needs: linting-done
-    runs-on: ubuntu-latest
-    
-    name: "Complement Workers (develop only)"
+          - arrangement: workers
+            database: Postgres
 
     steps:
       # The path is set via a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on the path to run Complement.
@@ -406,7 +363,7 @@ jobs:
 
       - run: |
           set -o pipefail
-          WORKERS=1 COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
+          POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
         shell: bash
         name: Run Complement Tests