A test that catches the bug your feature tests can't see

There's a class of bug that's maddening: it passes every test you have, then crashes in the user's face. I hit one in the admin UI of laravel-config-sso today, and the real fix wasn't changing an icon name — it was writing a test that could see the bug in the first place. The bug: wrong icon name, crashes only at runtime The admin UI uses Flux . Flux resolves icons through <flux:delegate-component> , and it throws for a name that doesn't exist: Flux component [icon.ellipsis] does not exist. It's an easy mistake. Flux ships Heroicons , not Lucide. So your Lucide reflexes lie to you: You type (Lucide) Flux wants (Heroicon) ellipsis ellipsis-horizontal trash-2 trash eye-off eye-slash Why feature tests don't catch it Here's the interesting part. I had a feature test that hits the admin route and asserts 200. Green. But the real UI crashes. How? Because in the headless test harness, Flux renders icons as no-ops. No real <flux:delegate-component> boots, so the icon name never gets resolved. The crash only surfaces under a full boot ( testbench serve ) — exactly where your automated tests don't go. Analogy: it's like a spell-checker that only runs when you print the document, not while you type. Your tests type away happily. The crash waits at the printer. The fix: a static test that reads the Blade and validates every icon Instead of relying on runtime, I wrote a Pest test that reads the Blade view, extracts every icon name (static and inside dynamic expressions), and asserts Flux actually ships a stub for each one: $fluxIconStubs = base_path ( 'vendor/livewire/flux/stubs/resources/views/flux/icon' ); it ( 'only references Flux icons that exist' , function () use ( $fluxIconStubs ) { expect ( is_dir ( $fluxIconStubs )) -> toBeTrue ( "Flux icon stubs not found" ); $view = file_get_contents ( __DIR__ . '/../../resources/views/livewire/sso-providers.blade.php' ); // Static `icon="name"` plus quoted tokens inside dynamic // `icon="{{ $cond ? 'eye-slash' : 'eye' }}"` expressio