diff --git a/app/tests/unit/MockSerializableKVStore.php b/app/tests/unit/MockSerializableKVStore.php
index 393e196..7c9faac 100644
--- a/app/tests/unit/MockSerializableKVStore.php
+++ b/app/tests/unit/MockSerializableKVStore.php
@@ -30,7 +30,10 @@ public function fetch( string $site_id, string $entity_type, array $entity_ids,
 
 	public function add( string $site_id, string $entity_type, array $entities, int $ttl = -1 ): bool {
 		$this->init_site_entity_type( $site_id, $entity_type );
-		$this->data[ $site_id ][ $entity_type ] = array_merge( $this->data[ $site_id ][ $entity_type ], $entities );
+		foreach ( $entities as $entity_id => $entity ) {
+			// merge manually instead of array_merge to not have PHP renumber integer keys.
+			$this->data[ $site_id ][ $entity_type ][ $entity_id ] = $entity;
+		}
 		return true;
 	}
 
diff --git a/app/tests/unit/Webhooks/CategoryWebhookControllerTest.php b/app/tests/unit/Webhooks/CategoryWebhookControllerTest.php
index 0ab4904..e045b3a 100644
--- a/app/tests/unit/Webhooks/CategoryWebhookControllerTest.php
+++ b/app/tests/unit/Webhooks/CategoryWebhookControllerTest.php
@@ -52,8 +52,7 @@ public function test_create_category(): void {
 		$this->request->method( 'getPayload' )->willReturn( new InputBag( $request_body ) );
 		$this->sut->serve();
 		$categories = $this->kv_store->fetch( $this->site_info->id, 'categories', array( '1' ), array( Category::class ) );
-		error_log( print_r( $categories, true ) );
-		$category = $categories[1];
+		$category   = $categories[1];
 		$this->assertEquals( 1, $category->id );
 		$this->assertEquals( 'Test Category', $category->name );
 		$this->assertEquals( 'test-category', $category->slug );