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

app/Transformers/RuleTransformer.php

@@ -28,6 +28,7 @@ use FireflyIII\Models\Rule;
 use FireflyIII\Models\RuleAction;
 use FireflyIII\Models\RuleTrigger;
 use League\Fractal\TransformerAbstract;
+use Log;
 use Symfony\Component\HttpFoundation\ParameterBag;
 
 /**
@@ -48,6 +49,9 @@ class RuleTransformer extends TransformerAbstract
     public function __construct(ParameterBag $parameters)
     {
         $this->parameters = $parameters;
+        if ('testing' === config('app.env')) {
+            Log::warning(sprintf('%s should not be instantiated in the TEST environment!', \get_class($this)));
+        }
     }
 
     /**