Dynamic environment setup

Author: emmadesilva

.github/workflows/test.yml

@@ -22,7 +22,11 @@ jobs:
       - name: Configure environment
         run: |
           echo "HYDE_RC_RUNNER_PATH=/tmp/hyde-rc-runner" >> $GITHUB_ENV
-          echo "HYDE_RC_BRANCH=$GITHUB_SHA" >> $GITHUB_ENV
+          if [ -z "$GITHUB_SHA" ]; then
+            echo "HYDE_RC_RUNNER_BRANCH=master" >> $GITHUB_ENV
+          else
+            echo "HYDE_RC_BRANCH=$GITHUB_SHA" >> $GITHUB_ENV
+          fi
 
       - name: Set up test runner
         run: php -r 'require_once __DIR__."/vendor/autoload.php"; \Hyde\RealtimeCompiler\Tests\Integration\IntegrationTestCase::setUpTestRunner();'