Learned that I should not refer to env vars directly so I removed all references.

app/Transformers/BillTransformer.php

@@ -56,6 +56,9 @@ class BillTransformer extends TransformerAbstract
     {
         $this->parameters = $parameters;
         $this->repository = app(BillRepositoryInterface::class);
+        if ('testing' === config('app.env')) {
+            Log::warning(sprintf('%s should not be instantiated in the TEST environment!', \get_class($this)));
+        }
     }
 
     /**