fix(bk): serverless-beats-tests start failing after merging #10734 (#10906)

Author: v1v

.buildkite/hooks/pre-command

@@ -34,9 +34,8 @@ if [[ "$BUILDKITE_PIPELINE_SLUG" == "elastic-agent-package" ]]; then
   fi
 fi
 
-if [[ "$BUILDKITE_PIPELINE_SLUG" == "buildkite-elastic-agent-integration-matrix" ]]; then
-  echo "Setting credentials"
-  # Set GCP credentials
+if [[ ("$BUILDKITE_PIPELINE_SLUG" == "buildkite-elastic-agent-integration-matrix") || ("$BUILDKITE_PIPELINE_SLUG" == "beats-agent-serverless-tests") ]]; then
+  echo "Setting GCP credentials"
   export GOOGLE_APPLICATION_GCP_SECRET=$(retry 5 vault kv get -format=json -field=data ${CI_GCP_OBS_PATH})
   echo "${GOOGLE_APPLICATION_GCP_SECRET}" > ./gcp.json
   export GOOGLE_APPLICATION_CREDENTIALS=$(realpath ./gcp.json)

.buildkite/pipeline.yml

@@ -344,6 +344,25 @@ steps:
       commit: "${BUILDKITE_COMMIT}"
       branch: "${BUILDKITE_BRANCH}"
 
+  # Trigger for pull requests - Serverless Beats Tests
+  # this should help detecting issues earlier in the development cycle
+  - label: "Trigger Serverless Beats Tests"
+    if: build.pull_request.id != null
+    plugins:
+      - monorepo-diff#v1.2.0:
+          diff: "git diff --name-only origin/${GITHUB_PR_TARGET_BRANCH}...HEAD"
+          interpolation: false
+          watch:
+            - path:
+                - .buildkite/serverless.beats.tests.yml
+                - .buildkite/scripts/steps/beats_tests.sh
+                - .buildkite/hooks/pre-command
+              config:
+                trigger: "beats-agent-serverless-tests"
+                build:
+                  commit: "${BUILDKITE_COMMIT}"
+                  branch: "${BUILDKITE_BRANCH}"
+
   # wait for CI to be done
   - wait: ~