diff --git a/packages/kbn-optimizer/src/integration_tests/basic_optimization.test.ts b/packages/kbn-optimizer/src/integration_tests/basic_optimization.test.ts
index 93a7240849b949..5863e30f42d6fc 100644
--- a/packages/kbn-optimizer/src/integration_tests/basic_optimization.test.ts
+++ b/packages/kbn-optimizer/src/integration_tests/basic_optimization.test.ts
@@ -24,7 +24,7 @@ import { inspect } from 'util';
 
 import cpy from 'cpy';
 import del from 'del';
-import { toArray, tap } from 'rxjs/operators';
+import { toArray, tap, filter } from 'rxjs/operators';
 import { ToolingLog, REPO_ROOT } from '@kbn/dev-utils';
 import { runOptimizer, OptimizerConfig, OptimizerUpdate, logOptimizerState } from '@kbn/optimizer';
 
@@ -74,7 +74,11 @@ it('builds expected bundles, saves bundle counts to metadata', async () => {
   expect(config).toMatchSnapshot('OptimizerConfig');
 
   const msgs = await runOptimizer(config)
-    .pipe(logOptimizerState(log, config), toArray())
+    .pipe(
+      logOptimizerState(log, config),
+      filter((x) => x.event?.type !== 'worker stdio'),
+      toArray()
+    )
     .toPromise();
 
   const assert = (statement: string, truth: boolean, altStates?: OptimizerUpdate[]) => {