Run complement-crypto in CI (#4197)

* Maybe run complement-crypto

* Use existing checkout

* Test that things fail if crypto breaks

* Fix test; run only on merge queue

* Prettier

* Maybe get it working in a merge queue

.github/workflows/tests.yml

@@ -71,6 +71,24 @@ jobs:
             disable_coverage: true
             matrix-js-sdk-sha: ${{ github.sha }}
 
+    complement-crypto:
+        name: "Run Complement Crypto tests"
+        if: github.event_name == 'merge_group'
+        uses: matrix-org/complement-crypto/.github/workflows/single_sdk_tests.yml@main
+        with:
+            use_js_sdk: "."
+
+    # we need this so the job is reported properly when run in a merge queue
+    downstream-complement-crypto:
+        name: Downstream Complement Crypto tests
+        runs-on: ubuntu-latest
+        if: always()
+        needs:
+            - complement-crypto
+        steps:
+            - if: needs.complement-crypto.result != 'skipped' && needs.complement-crypto.result != 'success'
+              run: exit 1
+
     # Hook for branch protection to skip downstream testing outside of merge queues
     # and skip sonarcloud coverage within merge queues
     downstream: