diff --git a/apps/electron-backend-e2e/src/performance/zoneless-migration.spec.ts b/apps/electron-backend-e2e/src/performance/zoneless-migration.spec.ts
index dd6607fda..f9a67c9d7 100644
--- a/apps/electron-backend-e2e/src/performance/zoneless-migration.spec.ts
+++ b/apps/electron-backend-e2e/src/performance/zoneless-migration.spec.ts
@@ -19,8 +19,9 @@ const skippedDirectories = new Set([
     'test-stubs',
 ]);
 // Test-only files follow the repository's `.spec` / `.test` naming, with an
-// optional suffix (`.spec-stubs.ts`, `.test-helpers.ts`, `.test-stubs.ts`).
-const testOnlyFile = /(\.(spec|test)(-[\w]+)?|^test-setup)\.ts$/;
+// optional suffix of one or more segments (`.spec-stubs.ts`,
+// `.test-helpers.ts`, `.test-data-stubs.ts`).
+const testOnlyFile = /(\.(spec|test)(-\w+)*|^test-setup)\.ts$/;
 
 function listProductionSources(directory: string): string[] {
     const files: string[] = [];
@@ -84,6 +85,27 @@ test('the zoneless checklist lists exactly the components that are still Eager',
     );
 });
 
+test('the guard skips test-only file names and keeps production ones', () => {
+    for (const name of [
+        'player.component.spec.ts',
+        'serial-details.test-stubs.ts',
+        'dashboard.spec-stubs.ts',
+        'rail.test-data-stubs.ts',
+        'test-setup.ts',
+    ]) {
+        assert.ok(testOnlyFile.test(name), `${name} is test-only`);
+    }
+    for (const name of [
+        'player.component.ts',
+        'spec-utils.ts',
+        'contest.ts',
+        'latest-setup.ts',
+        'testing.service.ts',
+    ]) {
+        assert.ok(!testOnlyFile.test(name), `${name} ships`);
+    }
+});
+
 test('ticked checklist entries name files that exist', () => {
     for (const file of readEagerChecklist().done) {
         assert.ok(sources.has(file), `${file} is ticked but does not exist`);
diff --git a/docs/architecture/zoneless-migration.md b/docs/architecture/zoneless-migration.md
index fdf973bcd..84fdb1ede 100644
--- a/docs/architecture/zoneless-migration.md
+++ b/docs/architecture/zoneless-migration.md
@@ -154,8 +154,9 @@ files that still contain `ChangeDetectionStrategy.Eager`.
 - [ ] `libs/portal/xtream/feature/src/lib/serial-details/serial-details.component.ts`
 
 Test-only files that set Eager are not listed; they do not ship. The guard
-skips every `*.spec.ts` / `*.test.ts` file with or without a suffix
-(`*.spec-stubs.ts`, `*.test-helpers.ts`, `*.test-stubs.ts`, …),
+skips every `*.spec.ts` / `*.test.ts` file with or without a suffix of one
+or more segments (`*.spec-stubs.ts`, `*.test-helpers.ts`,
+`*.test-data-stubs.ts`, …),
 `test-setup.ts` and `test-stubs/` directories.
 
 ## Zone-dependent sites