diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e01a82d..c9142c8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -46,9 +46,10 @@ jobs:
       - name: Type check
         run: npx tsc --noEmit
 
+      # Hostname must match `services:` id. `localhost` breaks Gitea act_runner (Docker job).
       - name: Run tests
         env:
-          DATABASE_URL: postgresql://test:test@localhost:5432/dbis_test
+          DATABASE_URL: postgresql://test:test@postgres:5432/dbis_test
           JWT_SECRET: test-jwt-secret-minimum-32-characters-long-for-testing
           ALLOWED_ORIGINS: http://localhost:3000
           NODE_ENV: test